Reset
by Emotistic Optimistic
Summary: As Judge for King Asgore Dreemurr, Sans has seen a lot of strange stuff. But when he wakes up with the feeling that something is completely wrong, he decides it's time to investigate with the only monster who could know what was happening: Royal Scientist W.D. Gaster.
1. Reset

Something was off today.

Sans laid in his bed for a few moments, trying to figure out what it was that felt so… _wrong._ His room looked the same as it always did, even in the dark. He was still a skeleton. They were underground. He got up, switching the off button on his alarm as he did so—he didn't know why he kept setting it, he rarely slept anyway—and heading over to the room next door. Ever so carefully, he opened the door and peeked in. He was greeted by light snores accentuated by the occasional "Nyeh-heh-heh," and the light from the hall showed a pair of bony feet sticking out over the edge of the mattress. Aside from needing a bigger bed, everything seemed fine in Papyrus' room. He shut the door to let his little brother sleep, then headed back to his room.

The wrongness had subsided a bit, and he couldn't remember what his worry had been. Maybe a bad dream? He shook his head and opened his curtains, room filled with the red light from the Core.

Welp. Time to get ready to be Judge.

Nah, he should be more grateful about this. The gig really wasn't that bad: it got him and Papyrus free room and board, the protection of King Asgore Dreemurr, and hopefully a good view for when the Seal was eventually broken. And he'd gotten it all by taking out some jerk who'd come at him with a frying pan. So what if the hours were terrible and there was more waiting than action? Papyrus was taken care of and safe as anything out here—not to mention how much he LOVED helping with the puzzles—and Sans…well, Sans had something to do while he waited to get to the surface.

Still, he'd be absolutely lying if he said it wasn't a little exciting seeing that weird flower when he entered The Last Corridor.

Hands in his pockets, he walked over to it with a small frown. He crouched down to study it curiously; it looked like the ones Asgore grew in his throne room. But how could it have gotten all the way out h-?

"Howdy!"

Sans jumped at the greeting, nearly falling over. The flower laughed as the skeleton caught himself.

"Golly, I sure got you, didn't I?" it asked, a smile appearing in the center of its petals. Sans looked down at it for a moment, then let out a little laugh.

"You know what? You did, pal. Nice work," he said, sticking his hands back into his pockets. "So how'd you end up here, little guy? This isn't exactly a high traffic area for monsters."

"Oh, I'm not a monster! I'm a flower," the flower chirped back. "Flowey the Flower! And I've been here loads of times!"

Sans' bony brow furrowed. "Really?" He was sure he'd remember seeing a talking flower around here. He crouched down to be on Flowey's level. "So what are you doing here today?"

Flowey gave him a big grin. "I'm gonna see Asgore!"

Ah, an Asgore fan. They got plenty of those in here. Still, most never got past the entrance…he should probably tell Undyne to give the guards a little more training. Sans gave an apologetic smile. "Aw, sorry, buddo, I can't let you in to see him. After that last human, visits are by appointment only." He stood up. "But, y'know what? Since you went to all this trouble, I'll go tell him and we'll see if we can sort something out. Wait right here." He turned to walk down to the throne room, but was stopped by something wrapping around his ankle and pulling him back.

 _"This isn't a request, you idiot._ "

Sans whipped his head around; Flowey's face had changed from a cute smile to a horrific grin. It laughed.

"You've looked surprised _every time._ Gosh, it's a shame you can't remember."

Every… _what_? Sans shook his head and tugged his foot away from Flowey's vine, eye glowing blue.

"I'd _really_ suggest leaving now if you d—"

"If you say 'if you don't want to have a bad time,' I'll reset right now," Flowey snapped. "The least you could do is be _creative_."

Re- _what?_ It took all of his training to keep his focus on the threat rather than the nonsense Flowey was spouting out. But still…how had he known what he was gonna say? As the thought crossed his mind, a smug smile appeared on Flowey's face.

"Aw, that's right, you don't know what I'm talking about. I'd explain, but what's the point if you're just gonna _die anyway_?"

Sans let out a cry of surprise and jumped back as a wave of white pellets shot at him, grunting as one grazed his arm. He grit his teeth and held up his hand to pull Flowey from the ground; an uprooting should take care of the damn weed. His eye flickered as he realized it wasn't doing anything. A chilling laugh erupted from the flower.

"Is that your levitation trick? That only works on _souls_ , moron." Another wave of pellets came at him, but this time he was ready, diving away without a hit.

"No soul? Glad you made no _bones_ about it," he grunted.

"Was that a pu-" Flowey was cut off as he was assailed by wave after wave of bones. Sans couldn't help his smile; he'd _always_ wanted to say that. He shot off another attack before Flowey could regroup. As he prepared a third, the wilting flower cried out, "Mercy!"

Sans paused, eye still glowing blue. "And why should I spare you?" he asked coldly. "You _just_ tried to kill me, and I'm really doubting you wanted to meet Asgore for tea."

Flowey took a few moments, then said, "You're the Judge, right? You're supposed to judge me on everything I've done, not what's happened right now."

Sans frowned hard. "All right, fine." He held his hands out. "I'm all ears. Tell me what you've done."

With some difficulty, Flowey looked up, the ghost of a smile flickering on its face. "Heh…" It looked down again, then pulled itself up and looked up at Sans with a wide, ghastly smile.

" _Why don't you pay attention this time around?_ "

"Wh—"

…

Something was off today.

Sans laid in his bed for a few moments, trying to figure out what it was that felt so… _wrong._ His room looked the same as it always did, even in the dark. He was still a skeleton. They were underground. He got up, switching the off button on his alarm as he did so—he didn't know why he kept setting it, he rarely slept anyway—and heading over to the room next door. Ever so carefully, he opened the door and peeked in. He was greeted by light snores accentuated by the occasional "Nyeh-heh-heh," and the light from the hall showed a pair of bony feet sticking out over the edge of the mattress. Aside from needing a bigger bed, everything seemed fine in Papyrus' room. He shut the door to let his little brother sleep, then headed back to his room, but stopped halfway there.

No.

This was all wrong.

Hadn't this happened before?

Sans held his skull. This couldn't have happened before. He'd remember it. But this was _so much stronger_ than déjà vu. He felt a chill crawl down his spine. Had something happened? Something he couldn't remember?

He'd heard guards whisper to each other about how they felt like they were forgetting something, or that something strange was going to happen, but for the most part they were shrugged off as a result of doing the same thing day after day. No one ever thought too seriously on it. But maybe now would be a good day to start thinking seriously. Something told him that whatever had happened put Asgore at risk, and as the final defense before the throne room, there was no way he could leave it be.

He quickly got ready and went to New Home as fast as he could. He had to be there in case anything happened. And after that, he needed to go to someone who would be able to look into this. Maybe who already knew what was happening.

He needed to go to Gaster.


	2. Gaster

A/N: Just as a quick note, I don't anticipate updating this fast on a regular basis (I've been sitting on this chapter for about two weeks now, before I wrote the first, and I'm impatient to get it up.) That said, the plan is to update ever 1-2 weeks!

Thanks for reading!

* * *

Despite the dread that sat in his stomach—well, lower abdominal cavity—throughout the morning, nothing happened. There was no threat, no ambush…nothing. To say Sans was having second thoughts was an understatement—he was on his third or fourth thoughts halfway through his shift. Even so, he'd heard too much from others to discount what he was feeling. And, once his lunch hour hit (Asgore was adamant that his guards have breaks), he was off to Hotland to find W.D. Gaster, the Royal Scientist.

As he reached the lab, he couldn't help but be nervous. Despite being a household name, no one knew much about Gaster. He was the Royal Scientist, yes, but he had zero public presence. Sans didn't even know what the man (maybe woman? W.D. could stand for anything.) even looked like. What if he was bothered by the intrusion? Sans hesitated at the door. This was a bad idea. He wasn't even sure that the threat was real; he was going off of what some dumb guards had said and his own unfounded anxiety.

He puffed out a breath. No. He couldn't do this. There was no need to bother the Royal Scientist, who really was probably very busy and probably had, like, eight experiments going on right now. He turned and started to walk away.

 _Hsst._

Sans stopped at the sound of hydraulics. Slowly, he turned around. The door was open, and in the bright light, a tall, dark figure towered in the doorway, nearly reaching the top.

"Ah, the Judge has paid me a visit."

The voice was hoarse and strange—it seemed as though it struggled with the words—and something at the shadow's midsection fluttered. Sans took a step back, sockets narrowing.

"How…how did you know I was here?" he asked, tense. The shadow laughed.

"I have, er, cameras. For protection," he said. A long, thin arm pointed up. "The light is not good here, but look closely."

Sans looked up, and he relaxed slightly. "Oh, surveillance cameras."

The shadow's head bobbed. "Yes, yes." It stepped back. "Please, come inside." Sans could make out a smile. "It has been a long time since I have seen one of my own kind."

Sans frowned curiously, but followed him inside and took a good look at the scientist before he smiled. "Oh my god, another skeleton!"

Gaster smiled and took Sans' hand to shake. While he was definitely a skeleton, his skull had two large cracks above and below each of his respective eye sockets, and both of his hands—which seemed to be in continuous motion when he spoke—had jagged gaps in his metacarpals. He gave a small laugh as he caught Sans inspecting him.

"Being Royal Scientist is a dangerous job," he said with a shrug, then motioned for Sans to follow him. "I am sure that being Judge has its dangers as well." He looked over his shoulder and smiled down at Sans. "I am surprised we have not met before, considering we have the same, er…" His hands fluttered again, apparently trying to motion the word. Sans smiled.

"The same boss, yeah." He stuck his hands in his pockets. "The language is a real bitch, isn't it?"

Gaster tilted his head. "I do not understand what you mean."

"I mean it's hard to speak. My parents had the same problem when they moved down here."

Gaster shook his head with a wry smile. "It is a curse. However, I do not let it stand in the way of my work." He guided Sans up to the second floor, which seemed to be a mix of lab and library. "Would you like any tea, Judge?"

"Call me Sans. Judge makes me sound a little, uh, intense." He checked his watch. "And I really don't have time; my break'll be over pretty soon."

Gaster nodded, then looked at Sans curiously. "Then I am assuming you have something you wish to discuss?"

Sans was still for a moment. He was in the presence of one of the greatest minds of the Underground; did he really want to bring up a silly déjà vu question? He looked at the ground, then nodded.

"Yeah…yeah, I, uh…I've heard some talk about people…feeling like they've already done, uh, certain things. And that they've forgotten things?" He huffed and rubbed his neck. "God, it sounds stupid when I say it like that. But…y'know, they've felt like they've already, uh, lived through a day. Like déjà vu. I thought it was just a normal thing, but…but I think I got that feeling this morning." He sighed. "That probably doesn't make sense at all."

"No, no! I understand perfectly!" Gaster said eagerly, pressing his long fingertips together. "What precisely were you feeling this morning? Spare no detail!"

Sans blinked. "Uh, well, I woke up and something just felt…off? And so I went and checked on my brother to make sure things were okay with him, and then I started to get ready and…I mean, it felt so much _stronger_ than déjà vu. Like, like I had done _all of that_ before, and that something bad was going to happen when I got to work."

"And what happened when you got to work?" Gaster pressed. Sans shook his head.

"Nothing. I just waited in there, like every other day. No one came."

Gaster nodded. "Good, good," he murmured. "Here, come with me. I think you will understand." He beckoned for Sans to follow him to a chalkboard with strings of odd symbols scrawled across it. Sans frowned.

"Is this code?" he asked, pointing to the symbols. Gaster, grabbing pages of notes from a nearby table, glanced up, then gave a sheepish smile.

"No, no. That is, er, my language. It is not much in use now, so I do not expect you to know it." He shrugged "And it is easier for me to write when I have complicated information to sort through." He chuckled as he looked through the notes. "You are lucky to have grown up down here. You can be understood."

Sans smiled wryly. "Well, I wouldn't call it _luck_ , but I guess it's convenient." He blinked as Gaster shoved papers in front of him.

"I have translated these notes for my apprentice, but she will not mind if you use them now. But I will still say what I can now. You see, I have a theory." Gaster's hands were moving at top speed, moving in time with his words in a strange sort of sign language. "Time as a whole is inherently unstable, but I believe it is even moreso down here. I suspect it is to do with the high concentration of magic. Magic is like…like a liquid." He picked up a beaker of water, holding it up for Sans to see. "See, in the glass it is concentrated and, er, the word for, er…" He let out a frustrated huff, then dipped his finger into the water. "You can do this."

"You can touch it?" Sans suggested.

"Yes, yes, that is it, but more. You can…immerse? Yes, immerse yourself into it. But, when it is out of the container…" He pushed aside some paper and poured the water out on the table. "It spreads. It is not so concentrated. It is still there, but it cannot be felt like it can when it is contained. That is why we were so much weaker when the humans attacked us, but so much stronger down here."

Sans frowned. "This, uh, it's really interesting, but what does this have to do with the déjà vu thing?"

Gaster chuckled. "You do not think like a scientist," he said. "But I will be brief. I believe that time here is affected by the high concentration of magic. It becomes more…more malleable, I think is the correct word. It can be shaped." He pressed his fingers together again. "You see, humans have a strange ability when they are down here that I do not think they have above ground. They are able to do something called 'reset'."

 _Reset._ Now why did that sound so familiar? Sans frowned, mulling it over. "So, um…so like what you do in a video game?"

Gaster blinked, and he tilted his head curiously. "I am not familiar with, ah, 'video game'."

Sans gave a little smile. "They're human things. Sometimes they wind up in the dump," he explained. "But if you want to play the game over, or if you mess up, then you can start over."

Gaster's socket's widened. "Oh! Yes, yes! That is exactly it, Sans!" He turned back to the chalkboard and flipped it around to the clean side, scribbling wildly as he spoke. "You see, humans do not have much in the way of magic. A little, but not nearly the amounts monsters do. _But_ they have significantly more substance—not just their souls, you see, but also their physical bodies. They are static; monsters are not. So, with enough concentration, they are able to…ah, to turn back time, to go back to when they first arrived down here." He stepped back, tapping the chalk to his teeth as he looked at the complicated diagram he had drawn. "I do not know if it is conscious or innate. I have spoken to a few of the humans—before they, ah…before their souls were used—but none of them seemed aware of what they were able to do." He sighed, setting the chalk down. "But perhaps that is for the best. That would only put off their inevitable fate."

Sans studied the chalkboard hard, ignoring Gaster's musings as he tried to make sense of this. So humans could travel through time down here? More than that—they could completely start over. How would that affect the underground? Maybe he had run into a human…no, that couldn't be right. He was sure he would know if he'd encountered a human—he could _definitely_ beat a human. His sockets widened, and he looked up at Gaster.

"What about…what about _monsters_ who want to reset?"

Gaster looked at him strangely for a moment, then stooped to pick up some fallen papers. "You know, you are not the first to ask me this."

Sans tensed. Maybe…maybe the _thing_ that whatever caused this forgetting _wasn't_ human; maybe it was a monster. _And maybe it was working with Gaster_.

"Who else asked?" he demanded, taking a step toward the other skeleton as he stood up and set the papers down.

Gaster looked up, then held his hands up. "Please turn your eye off. I know what you can do, and I do not enjoy being threatened," he said coolly.

Sans blinked. _Oh._ He hadn't even known he'd done that. He let out a breath and cooled down. Once he was calm, he muttered, "Sorry."

"It is fine, Sans." Gaster gave him a small smile, then continued. "I have been approached by several other monsters about this subject. I cannot remember exactly who—I suspect it is because of the resets—but I am certain that this conversation has happened many times." He crossed his arms, but his fingers continued to flutter. "I can only assume that whatever worried you this morning is responsible for these resets, and perhaps others have encountered it as well. Perhaps even including myself."

"Maybe we could find them," Sans said quickly, brain whirring. He had a definite lead with Gaster's information; maybe there really was something here worth investigating. "We could…maybe we could find these monsters and compare what we remember. And then we could figure out what this thing is!"

Gaster tapped his fingers against his teeth, looking dubious. "But they would have no way of remembering." He shrugged. "We may not even remember this if there is another reset."

"Then we'll have to think fast and figure out a way _to_ remember," Sans replied firmly as his watch began to beep. He looked down; break was over, he needed to go back to work. He looked down at the pages he still held. "Can I take these with me?"

Gaster waved a spindly hand. "Be my guest." He smiled. "And please, do feel welcome to return. It is nice to find another skeleton."

Sans gave a little smile to the other skeleton, then waved and hurried out of the lab and back to work. Time to figure out what the hell was going on with these resets.


	3. Brother

"Sans."

 _Grunt._

" _Sans_."

"Guhhh..."

"Sans, this is important!"

Sans slowly opened up a socket, only to be greeted by his brother's eager face filling his entire area of vision. He sighed.

"Papyrus, we've talked about this. I need to sleep on Sundays; they're my day off."

"I know, I know, but this is _important!_ "

Sans sighed again, then sat up, resting his cheekbone on his fist as he looked at his brother. "All right, bro. Tell me what's up."

Papyrus jumped up to his full height, practically bouncing in place. "I've been talking to Undyne!"

Sans managed a tired, little smile. "I heard you've been following her for the past few weeks. Guess she's real _spears_ -cial, huh?"

Papyrus' excited grin promptly dropped into an expression of annoyance. "Sans, this is _serious_."

"No, no, I know. I'm _dyne_ to know wh—"

" _Sans!_ "

Sans laughed. "All right, all right, I'm done. What's Undyne say?"

The excitement promptly returned; Sans half-expected Papyrus' neck to start stretching. "She says that, if I can make my own _special attack_ , she'll—listen, listen!—she'll _consider_ letting me do training to join the Royal Guard!"

Sans yawned. "Very cool. Glad you told me. I'm gonna sleep for a bit more."

"Wait, wait! I need your help!"

Sans opened his eyes again. "Huh?"

Papyrus rocked himself on the balls of his feet. "Well, I mean, you already know your special attacks. So I thought you could show me what to do. I can do normal bone attacks—I can even do some _really cool ones!_ —but special attacks..." He gave a helpless shrug. "So maybe, since you don't have work...?"

Sans sighed and rubbed his forehead. The plan today was to go back to Gaster and work out more on these resets. Apparently he'd managed to get a few monsters who had the strange déjà vu feeling and were willing to look into it with them. They'd be coming tomorrow, so today was for researching and coming up with a clear game plan of how to proceed with the research. Not to mention that the Royal Guard was the _last_ place he wanted his baby brother to be. But...god, the way Papyrus was looking at him with those puppy-dog eyes (though how he managed to do that with no _eyes_ was a mystery.) He shook his head.

"All right, here's the deal, Pap. I've got something I _really need_ to do today. It's really important. But...but I shouldn't be out too late. So when I come back, I _promise_ we can practice and start figuring out a special attack for you. Deal?"

Papyrus looked at his brother suspiciously. "Is this a normal promise or a _real_ promise?"

Sans blinked. "What do you mean?"

"Well, because you always say 'I promise' and then it doesn't happen." He started ticking things off on his bony fingers. "You promised to explain what your job is, you promised you'd practice with me two weeks ago, you promised you'd watch Mettaton's Winter Spectavaganzabration with me...but then you _don't._ "

Sans inwardly squirmed as Papyrus laid out the different ways he'd let him down; _god_ , did he really promise that much? He never even thought about it.

"I mean, I understand your work is very important! And that you do a lot!" Papyrus quickly added. "And I figure you must always have a good reason for not doing things with me!"

 _Goood_ , that made it so much _worse._ Sans covered his face; the last thing he wanted to do was let down his brother again. He was just so... _trusting._

"No, really, this time I really mean it," he assured once he looked up. "We'll make sure you have the most kick-ass special attack." He gave an uneasy smile. "They'll be _begging_ you into the Royal Guard."

Instantly Papyrus was back to Lesser Dog levels of excitement. "Really? Do you think so?"

Sans smiled. "Absolutely." He got up and stretched. "Why don't you practice making your bone attacks super cool while I'm out? That's the first step to getting a good special attack."

Papyrus nodded eagerly, jumping up and bounding away with a bright "NYEH-HEH-HEH." Sans smiled after his brother, then got up. Once they finally got out of here, he'd need to spend more time with Papyrus. And stop breaking so many promises.

To his surprise, Sans actually really enjoyed all of this science stuff. He'd pored over the notes Gaster had given him, reading as carefully as he could until the words actually made sense, and coming over for his lunch breaks to discuss parts of it he didn't understand.

So far, based on each other's experiences and Gaster's theories, they'd been able to surmise that there was a high chance of time travel being possible in the Underground. Whether it was contained to humans alone or monsters as well remained to be seen, but hopefully the group they would get together would be willing to help. This project was far too ambitious for just two monsters—they were already swamped with the information they had to sort through and think over now.

But Sans wasn't about to be overwhelmed. He had three different books open and was jotting down as many notes as he could, not letting any stray thought get away. With such an intense focus, he nearly fell off the chair when a cup and saucer clanked down beside him. He looked up to see Gaster giving him a smile before sitting beside him.

"I think now would be a good time for a break," he said, taking a sip from his own cup. "You have not looked away from those books since you came in."

Sans gave a wry smile. "Well, I'm trying to think like a scientist."

Gaster smiled proudly. "It is always nice to see someone find enjoyment in this work, particularly when it is something new for them." He nodded toward Sans' notes. "Do you mind if I take a look?"

Sans shook his head as he blew on his tea. "Go ahead. Dunno how much sense it makes, though; I was just writing what came to mind."

Gaster leaned over and took a few of the pages, looking them over quietly as he sipped his tea. His browbone rose, and he glanced up at Sans. "Your language is rudimentary, yes, but you surprise me with your process. It is quite sound."

"Heh, really?"

Gaster nodded, looking hard at Sans' notes before grabbing a page of his own. He examined both in silence for a moment, then looked back up at the other skeleton. "Your conclusions are the logical extensions of my own," he murmured, more to himself than Sans, but he looked up with a bright smile. "Have you considered going into science before?"

"Me? God, no," Sans said with a laugh. "I always figured I was a...y'know, brute-force kind of guy."

Gaster set the notes down and took his cup again. "Ah, yes. I forget that being Judge is primarily a defense position." He took a sip. "How did you come to that position, if you do not mind answering? You are very young."

Sans frowned. "Not that young. Undyne's head of the Royal Guard, and she's younger than I am."

Gaster sighed. "Yes, I suppose that is true. Another effect of life down here. You are forced to grow up very fast."

Sans smiled wryly as he set his empty cup down. "I would have anyway. Mom and Dad checked out pretty early."

Gaster gave Sans a sympathetic look. "In the war?"

The smaller skeleton shook his head. "Nah, Papyrus and I were both born down here." He shrugged. "I don't know what happened, really. Maybe the change was too hard on them or something." He smiled wryly. "Or maybe me and Pap are boss monsters and we just don't know it."

"I am sorry, but I do not think that you would be..."

Sans waved his hand. "It's a joke, Gaster, don't worry. I know I'm not a boss." He let out a little huff, resting an elbow on the table. "Papyrus doesn't remember much about them; he was still in striped shirts when they went to dust. So I've taken care of him since then. That's why I took the job when Asgore offered a few years ago; it gave me a way to make sure Papyrus was taken care of while he grew up." He rubbed his neck. "I do wish I could spend more time with him, though... _wait._ " He looked down at his watch. " _Shit!_ Is it really this late?"

Gaster blinked, then looked at the industrial clock on the wall. "Yes, your clock is correct..."

" _Shit shit shit!_ " Sans launched himself off of the chair. "I need to go! I told Papyrus I'd help him hours ago!" Without so much as a goodbye, Sans bolted back out to the Core.

He made it through the core in record time, bursting through their house's door hard enough to strain the hinges.

"Pap! Hey, Papyrus!" he called as he ran inside. "Pa...oh."

Sans found his brother sitting on the sofa, obviously in what he would consider his "battle clothes," and fast asleep. How long had he been sitting here, waiting for Sans to come home? Sans let out a sigh as his brow knit.

Another promise broken.

He stood for a moment, watching Papyrus snooze as guilt washed over him. A few years ago, he would have been able to pick him up and carry him to his bed, but that was hard now, what with his little brother being almost double his height. He took a breath and held up his hand, left eye a soft, glowing blue. As gently as possible, he lifted Papyrus into the air, trying not to wake or hurt him. Slowly, very slowly, he carried him up to his room and laid him on the too-short mattress. Papyrus stirred and mumbled something, but didn't wake up. Sans took the opportunity to pull the blankets up over the sleeping skeleton, then sighed.

"One day, buddy. One day I'll have time," he murmured, then headed back to his own room for what would no doubt be another sleepless night.


	4. Meeting

This was the big day; they were going to get the research group together. Or...at least try and convince some monsters to think about it with an informational meeting. Sans couldn't help but be nervous as he waited in the lab. What if no one decided to show? Or if they did, but got too freaked out and left? How would they be able to proceed with the research if either of that happened? There was Gaster's assistant—or apprentice? He kept mixing up the words when he mentioned her—but she was already doing an in-depth study on something called "determination," and apparently she wanted absolutely nothing to do with messed-up timelines. God, they should have chosen a better way of getting the word out; how would anyone take flyers asking "Feel like you're living the same day over and over? Then come to the Royal Lab to discuss it!" seriously?

Sans rubbed his face as he sat down. Regardless of whether they had more people working or not, there was going to be Asgore to deal with. Gaster had promised he'd talk to the king and made sure that he knew this was something important, and that Sans's role in it was absolutely critical. But what if Asgore said no? Or what if he said yes? Then how would Sans manage to juggle his job AND this research? And when would he have time for Papyrus?

He looked up as a hand fluttered onto his shoulder, catching Gaster giving him a reassuring smile.

"I did not think I would ever see you worried," the scientist said with a small laugh.

"I'm not worried!" Sans quickly assured. "This is gonna be fine. It'll be great. We'll…hopefully have people show up, and I'll tell them the science stuff, and if no one comes that'll be fine, we'll figure stuff out and god, no one's gonna come, are they?" he finished, dragging his fingers down his face.

Gaster's smile didn't waver, and he pat Sans' shoulder. "Do not worry. If no one comes, then we will find a way to proceed. I cannot tell you how many experiments I have done on my own, and they have all ended well." He shrugged. "Most have ended well," he amended, holding up his hands with a wry smile. "And I will make sure that I take the brunt of any injuries; a few more cracks will not be an issue. Asgore tells me it adds, er, _character,_ I think is the word he used _._ "

Sans looked up with a little smile. "Heh." He looked down at his notecards. "Well, a couple people have to be interested, right? We can…I'm sure we can work with that."

Gaster smiled and pat the other skeleton's shoulder. "Spoken like a scientist," he said before returning to the timeline diagram.

Sans let out a breath. Just a few people. He could do this.

* * *

He couldn't do this.

Sans stared at the monitor in quiet horror. An _ocean_ of monsters were outside the door; fish people, bunny people, lava people, _so many dogs._ He had just gotten himself ready to deliver a talk to a handful of monsters, not a whole audience!

Even Gaster—prepared-for- _anything_ Gaster—looked surprised as he saw the turnout. He looked down at Sans. "I did not realize so many knew of resets."

Sans managed a tight smile. "Maybe they just came to see you," he joked. Gaster frowned.

"That is ridiculous, Sans." He looked at the monitor again. "Well. I suppose it is time to let them in. Are you still able to do the speaking?"

Sans swallowed. "Don't have much of a choice, do I?"

Gaster looked at him apologetically. "I could manage, if you are nervous. I just…worry I will not be clear."

"Seriously, Gaster, it's fine." Sans gave him another weak smile. "Anyway, I always wanted to go into show business." He let out a breath, then hit the button on the console to open the door.

As was to be expected, the monsters came in waves. A few chairs had been set up in the lab, but those were quickly taken and soon enough it was standing room only in the small lab, the excited conversations—and a few yips—bouncing off the lab's walls. Sans stared at them from his place in the front. _God._ Well, they wouldn't need to worry about not having enough help with the research.

Finally, he cleared his throat. That did nothing. He tried clapping, but still nothing. Finally, sucking in a deep breath, he shouted, " _We're starting!_ "

That did it. Silence settled over the group, and all eyes were eagerly on him and Gaster. He tried to put on his most convincing smile.

"Hi, uh, everyone. Glad so many of you came," he said, acutely aware of all the eyes on him. Surprisingly, the nauseous feeling he'd been fighting since arriving at the lab was gone. Maybe he could do this. "So, uh, I'm Sans, and this is Dr. W.D. Gaster." Gaster smiled at the group, and there were quite a few whispers of "Oh my god, so _that's_ him!"

Sans glanced up at Gaster at the response, then back at the group. "Yeah, that's him. So if you just came to get a look at the Royal Scientist, there he is. You're good now." His face dropped as 95% of the group shuffled back to the door. Oh, god, was that _really_ why they all came? _Shit,_ of course it was. Nothing creates interest like the mysterious royal scientist in the mysterious royal lab.

Once the room finally drained, a group of eight were left, all eagerly looking at Sans and Gaster—who were both still staring at the door. One fish-girl raised her hand and waved the flyer with the meeting information.

"Um, hi! So I've had the déjà vu thing loads of times!" she said, bringing the skeletons' attention back onto her. "Like, sometimes it feels like I've done the same thing five times in a row."

"Same here," piped up a rabbit. "I feel like something really bad had happened some days, but I can't remember what."

Finally recovered from his shock, Sans perked up as the rest of the group chimed in with their experiences. He grinned.

"Perfect! That's exactly what we're looking for!" he said excitedly. "See, we have a theory…well, Gaster has a theory and I've been working with him on it." Gaster pulled up a slide full of wiggly lines and arrows. "So, uh, basically, humans have the power to, uh, go back in time. But only down here. So some of those feelings of living through the same day over and over are from them. But…we think that monsters _might_ be able to do that too…so…we want to research that. But we need more monsters on the team than just us." Sans gave the group a shrug with a smile. "That's the short of it, anyway. Obviously we'll explain more when we actually start the study. But, uh, any takers? I'd say it'd be pretty time-consuming, but there's a chance you might get it back," he added with a wink.

There was a little titter at the joke, and each of the remaining eight raised their hands. Sans beamed and glanced back at Gaster, who nodded.

"Great! This is…this is really great!" he said, turning back to the group. "All right, so let's talk some science."

* * *

The meeting was a roaring success—everyone involved had been completely on-board, and it was agreed that they would meet next week to start their research. With such a small group, they ended up breaking early. Since he'd taken the whole day off, Sans _finally_ had enough time help Papyrus with his special attack. They got barely anywhere with it, of course, but even so, Sans couldn't have asked for a better day.

Later that night, once Papyrus was tucked away in his too-small bed and had gotten his nightly bedtime story (A few years ago, Sans had suggested that maybe Papyrus was a little too old for bedtime stories, but the look Pap gave him was enough to break his heart. The stories stayed a nightly ritual.), Sans made his way back to Hotland and entered the lab. He'd had something on his mind, and it couldn't wait another day or he'd lose his nerve. Gaster, as he suspected, was still up and writing notes, and he jumped as Sans greeted him.

"You nearly made me dissolve," the older skeleton laughed as he composed himself. "One would think you could appear out of thin air."

Sans grinned as he pulled himself onto one of the chairs. "It's a special talent, I guess."

Gaster shook his head with a smile and returned to his notes. "So what has brought you here?" he asked, one hand fluttering as he wrote with the other. "I thought we agreed to wait until next week to begin our research proper."

Sans sat quietly for a moment, thinking over what he wanted to say. "Do you think…you could teach me your language?" he finally asked.

Gaster paused, then looked up at Sans. He was silent, then set his pen down and turned to face the other skeleton fully. "Why would you wish to learn such a difficult thing?" he asked, half his mouth turned up in a curious smile.

Sans shrugged. "Well, I mean, it'd make things easier with notes, right? If I knew what you were writing, then I could translate them word-for-word to the group," he said. "And…" He rubbed his top vertebrae. This was the part he was hesitant to mention. "And…I figured…y'know, it'd get me back to my roots. I never really got a chance to learn anything about what life was like back up above ground." He gave a small laugh. "Is it still considered 'roots' if they're above ground and you're underground?"

Gaster gave him a small smile. "I understand what you mean," he said. As he spoke, his hands moved with each word, each with a clear, definite movement, rather than his usual fluttering. "But my language would not have been yours if we were above ground."

Sans frowned. "What do you mean?"

Gaster sighed. "Skeletons…are strange," he said. "We lived separate from other monsters above ground for a long time—humans did not seem to be _as_ frightened by us—and so our linguistics did not follow the rules of the other monsters. It is difficult to explain…but I will try. It is good to know about the past.

"The skeleton 'language' is in actuality a compilation of several. You see, each family has a particular dialect—for instance, even though you grew up speaking the Underground's language, I can still hear traces of your family's dialect when you speak. However, each family having an individual language is not very…" Gaster frowned, hands curled with his pointer finger extended, moving over each other a few times. "…pragmatic, I think, is the right word. So a second language evolved for communal use." He smiled as he caught Sans's frown. "It is very confusing if you were not raised with it. You see, skeletons were very, er, clan-based. There was very little communication with those outside your family or very close neighbors—ultimately this was to our detriment; this is most of the reason why there are so few of us down here." He looked at Sans curiously. "Am I making sense?"

Sans frowned, brain trying to sift through this new information. "So if we were still above ground, Papyrus and I would mainly speak our parents' language?"

"Yes, precisely."

"Would it be _close_ to yours?"

"Not at all."

He frowned as he looked up. "Could you teach me the communal language, though? We would have shared that, right?"

Gaster shrugged. "Only if your family and mine had to negotiate something. It is very limited, and to be honest, I do not remember much of it. I only had need for it once or twice before moving down here."

Sans huffed, shoulders slumping. Well, so much for getting back to his roots.

Gaster tapped his fingers together as he watched Sans deflate. "If it is all the same, I was, er, unlucky with the language I ended up with. It would be very difficult to learn."

Sans looked up, curious. "Why?"

Gaster smiled a bit, then moved his hands in the same clear, definite way he had while he was explaining skeleton languages. This time, though, he didn't speak. Once finished, he set his hands in his lap. "It is all hand movements. I suspect I had an ancestor long ago who could not speak, and it simply evolved from there."

Sans blinked. _Oh._ That explained why Gaster's voice never quite sounded right—even though his parents had trouble speaking the Underground's language, it had never seemed like they struggled as much as the scientist did. He frowned again, looking down at his own hands.

"Do not feel bad, Sans," Gaster assured gently. "It is not practical, and I understand this language well enough."

Sans stayed quiet for a moment, then glanced up. He awkwardly tried to imitate a few of the hand movements with a smile.

"I know blood's thicker than water and all, but, well, we don't have either," he said with a shrug, then gave Gaster another small smile. "But we're both a bunch of bones and magic; that must be close enough to being family down here."

Gaster looked at him for a long moment, not saying a word. Finally, a wide grin spread across his skull.

"Yes, I suppose it must be," he said warmly, then held up his hands. "In that case, let me teach you the, ah, the…"

"Is that the sign for basics?"

"Yes! I will teach you the basics."


	5. Grillby's

_Flash!_

"Jeez, Ceris, you're gonna blind us!"

Ceris, a small dinosaur-type of monster with a very long neck, laughed as Sans rubbed his sockets. "You and Gaster said we're making history with this research, and it needs to be documented!" She looked at the photo as it printed out of the camera. "And I want to make sure the history books have _action shots._ "

Sans chuckled as she bounded off to take pictures of the other researchers before he turned back to the other two monsters at the table. "All right, so what was that you were saying about anomalies, Wynn?"

The rabbit, pupils still too-wide from the flash, blinked before tapping the paper in front of him. "Based on what I've read, any sort of anomaly could completely break the universe!"

Sans leaned forward, putting on a face of listening intently as Wynn explained his findings, but he wasn't able to concentrate. Really, he was too caught up in how great things were right now. Things were busy, yeah; he still had work and had to make sure Papyrus was all right—though _god_ , he wished he had more time with him. But even so, they were making amazing leaps with the study, and it was… _fun._ Between tests and research, they joked and chatted and were forced into pictures. And that was without everything he was learning from Gaster—after the rest of the group headed home, he and the scientist would sit and chat about the day's major discoveries or simply talk about the going-ons in the Core, with Gaster signing all the while and Sans imitating as best he could. Immersion, according to Gaster, was the best way of learning, and it seemed like it was true. After a few weeks, Sans was able to sign simple phrases without speaking; it was still tough, of course, but the look on Gaster's face when he saw the signs was incentive enough to keep learning.

He was broken out of his reverie as Terrin, the fish-girl who had spoken at the meeting, interrupted Wynn.

"Okay, hang on, did you get this from a _textbook_ or one of those human books from upstairs?"

Wynn puffed. "That shouldn't matter!"

"It does! Human books are _weird._ I've seen some where everyone has giant swords; I'm _sure_ humans don't have giant swords."

"It was a _science book_ , Terrin!"

"Okay, okay, hang on, let's cool down. No need to get _hopping_ mad," Sans interjected, earning a giggle from Terrin and a pained look from Wynn. "Anomalies obviously aren't great, but they're not tearing the universe apart just yet. If they were, there would have only been one reset and we all would have died."

Wynn frowned. "But it could be making the timelines weaker! If that's the case, than it's just a matter of…" He stopped himself, and Sans grinned.

"Say it."

" _No,_ Sans."

"Come on, say it. If you don't, I will."

"It's just a matter of _time_!" Terrin finished with a grin, leaving Wynn fuming nearly as much as Papyrus after a pun. Sans gave her a high-five just as Gaster whistled between two bony fingers, signaling the session was over.

"Excellent work," he said, sounding proud of the group (he always was). "But it is getting late, and I think it is best we break for the night."

" _Yess,_ time for Grillby's!" A lavaman, Tephra, pumped a gelatinous fist. The rest of the group gave a cheer, and Terrin turned to look at Sans.

"You should come with us! You always miss out!"

Sans half-smiled. "Well, y'know how it is. Gotta go to work tomorrow and all…"

Another _flash_ nearly blinded him. Ceris took the photo out and shook it, then held it out for everyone to see.

"And here you see Sans the Skeleton, who always put work instead of having fun," she said loudly, then looked back at him. "Seriously, though, you should take a break and come out with us! It's practically tradition that we all go to Grillby's on Fridays."

Sans glanced at them for a moment, then looked back at Gaster. As subtly as possible, he signed, "Okay?"

Gaster smiled at him, hands telling him, "Have fun."

Sans gave him a little smile back, then turned back to the group. "All right, but I really can't stay out too late." He grunted as Tephra slung a warm arm around his neck.

"Awww yeeaaahh, party at Grillby's tonight!"

* * *

Sans had been to Snowdin a few times, but only on the quickest patrols when there had been a threat of humans. He'd never actually met any of the locals or gone in any of the shops. He'd assumed Grillby's was some sort of diner, not…well, not a _dive bar._

He was finally shoved into a seat, looking around in a bit of a daze, as the group completely took over the bar.

"All of our usuals, and an order of fries for my buddy Sans here," Tephra called to what looked like a sentient mass of flames. He looked at Sans for a moment—well, the glasses near the top of the flames were directed at Sans—then nodded. Tephra grinned at the skeleton. "These are the best. Your tastebuds are gonna go into _orbit_."

Sans half-smiled and opened his mouth, pointing at the hollow bottom of his jaw. "Too late."

Terrin squeezed in on the other side of Sans, then grinned at him. "All right, so we've all been wondering, what's this mystery job of yours?"

"Hey, yeah! What's keeping you from all the fun?"

Sans glanced around at the group; all eyes were on him. Well…it was never really a _secret_ ; he just never told anyone. He smiled.

"Well, uh…you guys know _the Judge_?" he said, leaning against the bar for maximum drama for his reveal. The group collectively gasped.

"Oh, my god, the _Judge?_ " Ceris whispered. Wynn glanced around.

"I heard…I heard he can kill a human in _one hit._ "

"Well, _I_ heard he judges _monsters_ just as much as humans!" Terrin whispered. "God, I hope I never meet him."

As the group whispered, Sans' face fell. What? He knew that monsters knew that the job existed, but…well, it looked like his reputation preceded him. How did this kind of word even get around?

Tephra passed him the plate of fries, bringing him back to the moment. "So what's the Judge gotta do with you?"

"Uh…" Sans' brain whirred, trying to get a good lie. "I, uh, I do the paperwork for him." He gave the group a weak smile. "Y'know…have to make sure the, uh, the legal stuff's all squared away."

Terrin leaned closer to him. "So…what's he like?" she asked, voice hushed.

"Boring," Sans replied quickly. "Only cares about his work. But, uh, but he's not a _threat_ or anything." He managed another smile. "Unless you're going around hurting monsters. Then _jury-_ n trouble."

There was a combination of laughs and groans, and the tension dissipated into talk about everyone's respective lives. As the night went on, the group loosened up even more. Dares were made (Sans had to drink a whole bottle of ketchup, then he drank another just to show off; actually, it wasn't too bad.), Ceris started crying over how great it was that everyone was friends before she took loads of pictures, Wynn got in a heated argument with Apho over whether the humans were more likely to have laser swords or just _really big_ swords. In all, it was the best night Sans had had in a long, _long_ time.

* * *

Eventually, things wound down. Most of the group left, leaving Sans, Terrin, Tephra, and Ceris leaning on the bar in a quiet, collective stupor.

"Hey, guys," Tephra looked up at the group. "Real talk. What would you do if you could reset?"

Sans frowned. "Y'know, we really shouldn't even be thinking about that. We're just seeing if it's _possible_ for monsters…"

"Oh, don't be a spoilsport, Sans," Terrin said, giving him a little shove. "It's not like we can _actually_ reset."

Tephra grinned. "I'd go back and figure out how to get a job with MTT. I had _no idea_ that rectangle would get so popular."

"My turn!" Ceris announced loudly. "I'd move out _waaay_ sooner if I could go back. My mom was _suffocating_ me." She held up her camera with a tipsy smile. "Deffffinitely would have been a photographer if I'd done that."

"Well, _I'd_ do a complete makeover," Terrin said, patting at a fin. "I was way too hard on myself years ago. I bet I'd have someone steady by now if I had half the confidence I have now." She nudged Sans. "All right, Judge's Secretary, it's your turn."

Sans looked at them, then down at the empty ketchup bottle in his hands. "I'd work less," he said, then smiled. "I _hate_ my job; it eats up all my time. If I could go back, I'd ask for fewer hours, and I'd actually be able to spend time with my brother." He looked up as felt something on his shoulder; Ceris had reached her neck over to rest her head on it, looking at Sans with wide eyes.

"Oh my god, you love your brother SO. MUCH," she said, looking like she was on the verge of tears. "I just…you _love him. SO. MUCH."_

Terrin laughed and pushed her off of Sans. "And I think you love your drinks SO. MUCH." She got up, then boosted Ceris up as well, trying to keep the dinosaur's neck from flopping around. "I think it's time we get on out before she starts sharing her life story."

"I better get going, too," Tephra said, getting up and stretching with a few pops and sizzles. "Undyne'll have my ass if I come in late."

Sans half-smiled. "See you guys on Monday." While it had been fun, he needed to get home, too; Papyrus would be waiting for him if he hadn't conked out already. He left a tip for Grillby, then headed for the door.

On the way home, though, he couldn't help but think over going back. If he knew what he did now, he could definitely work part-time. That would mean a lot more time with both Papyrus and Gaster, and _that_ would mean a lot more research and no more broken promises.

He stopped outside the house; Papyrus' light was still on. He'd probably fallen asleep without turning it off. Sans sighed, then set his jaw.

He was going to do it.

He was going to figure out how to reset.


	6. Success

The next couple weeks, Sans threw himself into his research. He read on the job, he spent his nights writing formula after formula—every research meet-up, he brought armfuls of papers with new theories and findings. While they had taken great strides in their research before, now they were moving at lightning speed; they had come up with concrete theories of how humans were able to reset (Humans, everyone knew, are solid, yet comprised mostly of water. This meant they reacted with the magic of the Underground in the same way water did, which allowed them to move fluidly through timelines.) and potential ideas of how a monster would be able to reset. Their main theory was this: with a great deal of effort, a monster could _possibly_ force his own magic and dust to _float_ to a different timeline; it would not be wise, though, because there was a strong possibility that some of their being could be left behind. This also had the problem of not being sure where they would end up; without the solidity of humans, monsters weren't able to go back to a specific time—they had to work _with_ the Underground's magic rather than against it. In all, it was not a very viable option for monsters.

And that was that. The group had achieved their purpose; they understood resets, they figured out that it _was_ possible that a monster was behind the resets they had all felt before the experiment. The last research group dispersed with vague plans to have a party to celebrate their findings, and, like so many times over the past few months, Gaster and Sans were left alone in the lab again.

"I do not think I have ever had such a successful study with so few injuries," Gaster said brightly as he gathered their papers. "I will publish our findings tomorrow, and our mystery will officially be solved." He grinned up at the shorter skeleton, though his expression fell as he saw Sans hunched over a table, scribbling furiously. "Sans?"

Sans didn't reply, instead chewing on his pencil. No, no…no, that method wouldn't work. He grunted as he crumpled up the paper and threw it aside before starting a new formula entirely. He jumped as the ball of paper appeared in front of his sockets.

"May I ask what you are working on?" Gaster asked softly. Sans quickly took the paper from Gaster's hand.

"Nothing," he signed back with a weak smile. Gaster frowned and peered over his shoulder.

"It's not often I see a risk ratio for 'nothing,'" he signed, then let out a sigh. "Sans, I appreciate your willingness, but please do not put yourself in harm's way." He sat down beside Sans. "The study is over. We have done what we set out to do."

"Have we?" Sans asked, looking up at the scientist. "I mean, we just…we've opened up all these possibilities! And it seems like…it seems like we're not doing our jobs if we don't keep going."

Gaster gave him a wry smile. "Ah." He looked down at his hands and gave a small, wheezy chuckle. "It would appear that I have made you _too much_ of a scientist."

"Is that bad?" Sans asked, signing sharply to accentuate his point. "Just _one_ reset, and we'll have so much more information!" He glanced down as a fluttering hand landed on his shoulder.

"Or we could have you dissolve," Gaster said quietly. "And then where does that leave us?"

"I did the math! The odds of me _dissolving_ are really slim if I do this right," Sans argued. "Sure, there may be a few side effects, but I don't think that would really hurt. And the pros really outweigh the cons!"

Gaster sighed. "You are very, er, determined," he said. "And that is not a bad thing. You think you _can_ do something, therefore you _need_ to do it." He looked at Sans for a long moment. "But that is not always wise, Sans. And I would expect someone tasked with judgement to be more…more prudent."

Sans frowned hard, glaring at the paper in front of him. Gaster tapped his fingers together, then set his hand once again on Sans' shoulder.

"Perhaps you could aid my assistant and I in our research," he said softly, then smiled a bit. "And there is still quite a bit of vocabulary I have not taught you."

Sans didn't reply; instead, he tapped his pencil hard against the table. Gaster sighed, then drew back and stood up.

"Obviously I cannot dictate what you can and cannot do," he said, gathering the notes again. He looked at Sans with a pained expression. "But please. Do be careful, Sans. Delving into places you should not is how you end up looking like me, and that is in the best case scenario." He turned. "I will leave the lights on for you. Turn them off before you leave."

Sans listened as Gaster's footsteps faded away, and he let out a breath. This was worth it. It had to be. And…and the risk wasn't as big as it could be. He glanced back behind him; the lab was empty. He jumped down from the stool and looked at his notes. He just…needed to focus. It wouldn't be hard. It shouldn't hurt. He just needed to let his magic float to another timeline. It really couldn't be that hard, right?

He gasped in a breath; suddenly his chest was too tight. Was that a side effect? Had he done it wrong? What if he managed to reset and his ribcage had shrunk? Was that a thing that happened? He peeked down his shirt, just to check. Everything seemed in order…he shook his head, ignoring the sheen of sweat over his bones. No, he hadn't reset at all, just freaked himself out. He let out a shaky breath. He could do this. He just had to _focus_.

Just had to close his eyes…

Hope for the best…

And _go._

* * *

"Sans."

 _Grunt._ Oh, god, he felt so sick…had he drunk too much ketchup? No…

" _Sans_."

"Guhhh…" His head was throbbing. Could skeletons get migraines?

"Sans, this is important!"

Sans slowly opened up a socket; white and red swam into his vision, which didn't help his nausea at all. Eventually, the swirls of color formed themselves into his brother's eager face filling his entire area of vision. He sighed.

"Papyrus, we've talked about this. I need to sleep on Sundays; they're my day off." He hoped it was Sunday, anyway. He needed to sleep off whatever _this_ was.

"I know, I know, but this is _important!_ "

 _Wait._ He had woken up like this before. Ignoring how awful he felt, he sat straight up.

"Pap, are you gonna ask me to help with your special attack?" he asked quickly. Papyrus blinked, then narrowed his eyes.

"Have you been eavesdropping on my phone calls with Undyne?" he asked suspiciously. Sans stared at Papyrus for a moment, then grinned.

 _He did it._

He grabbed Papyrus' bony shoulders. "Tell you what, I need to go, but I will be right back here at seven _sharp_ , and then we will make sure you have _the most kickass_ special attack that'll leave Undyne _begging_ you to join the Royal Guard."

Papyrus' suspicion immediately turned into starry-eyed excitement. "Wowie! Really, Sans? You mean it this time?"

With a bit of difficulty, Sans got up out of bed and started walking Papyrus to the door. "I absolutely mean it." He grinned. "While I'm gone, make sure your normal attacks are as good as possible, all right?"

"Of course! The _Great_ Papyrus will have the best normal attacks!"

Sans stopped. "The Great Papyrus?"

Papyrus looked over his shoulder at Sans. "I…um…I thought that sounded cool," he said sheepishly. Sans blinked, then his face split into a wide grin.

"It is cool. It's _so cool_ ," he assured. Had Papyrus been calling himself this for months? How had he not known? "I think you should keep it."

Papyrus beamed. "I will! I mean, I, _the Great Papyrus_ , will!" Without any more prompting, he darted out of Sans' room with a bright "NYEH-HEH-HEH."

Sans smiled after him. God, just five extra minutes and he knew more about his brother than he had in months. He let out a breath and shut his door. He had to get to the lab; even without all the research, Gaster _had_ to know what had happened. He shut his eyes and let out a breath with a _whoosh_. He had to be calm about this. This was _massive_ , and it needed to be handled delicately.

"Sans?"

Sans's sockets flew open. Gaster stared back at him, looking as confused as he felt. Sans looked around. The lab? But _how_? And…oh, god, he was still in his pajamas.

The silence seemed to stretch for hours before Gaster finally cleared his throat and held up his mug.

"Shall I make another cup of tea?"

Sans felt his legs wobble, and Gaster was almost immediately on his feet to grab him before he fell.

"How…how did I get here?" He finally was able to get his voice out as Gaster guided him to a chair. "I…I mean, that's not possible, right?"

The scientist shrugged. "Your guess is as good as mine, Sans."

Sans pressed a hand to his skull. "It must…it must have something to do with the reset…" His sockets widened. "That's why I'm here! I did it, Gaster, I _reset!_ "

The scientist stared down at Sans curiously, then shook his head. "Whatever caused you to appear must…must, er…" His hands moved vaguely. Sans sat up.

"Confused! That's the sign for confused!" He waved his right hand while the left pointed to it.

Gaster stared at him, his own sockets wide. "How could you know that? It is a dead language."

"No, no! See, you've been teaching me your language for the past couple months." He smiled as he signed, "You see? It true."

Gaster's sockets brightened, but he shook his head and pressed a hand to his skull. "But…monsters _can't…_ "

"No! They can! The research group we're putting together, it works! We all researched for _months_ and figured that monsters can do it! And I just _proved it!_ "

Gaster shook his head again. "This is…hard to, er…" He signed with a grimace. Sans frowned and imitated the sign a few times.

"Digest. That's the word."

Gaster sighed. "Thank you." He looked over at Sans for a long moment, his face caught between disapproval and curiosity. He sighed again and covered his eyes. "Were you at home before you appeared?"

Sans half-smiled and gestured to his clothes. "Pretty obvious, I think."

Gaster shut his eyes and paced, his hands whirring too fast for Sans to translate. "And that was where you reset to?"

"Yeah. I was in the lab, and then I woke up in bed."

"So clearly there is no other Sans to worry about," Gaster muttered. "I can only imagine your, er, teleportation is a side effect of the reset. Obviously, I won't be able to tell you more until _I_ know more about resets, but perhaps you could look into why that may have happened." His brow bone creased. "You put yourself in a very tricky position."

Sans half-smiled. "What, because of the teleporting?"

The other skeleton shook his head. "No. You already know several months-worth of research, while I—and our research group—know next to nothing about it. You will either tell us what you know and confuse usor you will have to endure months of keeping quiet." He shrugged. "As a scientist, I cannot take your word at face value; I must have the research to, er, to support it."

"Oh." Sans shook his head. "No, it's fine. I can stay quiet…" He smiled a bit. "I think that's worth the opportunity to make things better."

Gaster didn't look nearly as assured, but he sighed and sat down. "I suppose there is no choice but to move forward, then." He looked at Sans for a long moment, his brain clearly working as hard as it could to rationalize what had happened. Finally, he lifted his bony shoulders in another shrug. "Well. I suppose doing more research would be pointless on your end. I will put together some diagrams with what we have." He gave Sans a wry smile. "No use spending the day here if you do not-"

" _No!_ " Sans interjected. "I can…I can bolster what you have!"

"It will be quick work."

"Then, uh, then maybe I can help with something else? At least until seven?"

A curious look flashed over Gaster's face, and his smile softened. "Perhaps I can teach you more of my language." His hands added, "Your grammar is atrocious."

Sans grinned, then glanced down at his clothes. "Should I go, y'know, get into normal clothes?"

"If you would like, though I find I do my best thinking in my robe and a pair of warm slippers," Gaster chuckled. "Regardless, I will get another cup for you." He got to his feet, then looked down, his hands fluttering. "Sans?"

"Yeah?"

"If _you_ are able to reset, then…I fear we are treading into far more dangerous territory than we anticipated." He looked up at Sans. "Please, Sans, do be careful. I do not know the implications of what you have done." His brow bone creased into a slightly pained expression. "I cannot help you with this."

Sans swallowed a few times as his stomach twisted, though this time not from nausea. "I…I should go change. I'll be back." He quickly got up and exited the lab as fast as he could. His chest tightened as he ran. Was he right in thinking that had been a side effect of the reset?

Or was he just realizing what a bad decision this had been?


	7. Side-Effects

"Are you ready, Sans?"

Sans back and forth onto the balls of his feet as he nodded. He was beyond ready; he was _pumped._ Gaster gave him a long, hard look.

"Now, remember…if you should feel, er, faint…or even nervous, then we do not…"

Sans smiled at the other skeleton, and he signed back, "We been doing this weeks. I be fine."

Gaster managed a weak smile and signed back, "Grammar, Sans. You have not been practicing." The smile died, and he shook his head as his hands whirred, "Regardless. Tell me and we will stop."

Sans gave him a grin, then set himself up to stand solidly, focusing on the wall on the other side of the lab. Gaster picked up his notepad.

"One end of the room to the other, then."

Sans focused hard on one tile on the other side of the room. His left eye glowed bright yellow as he felt the initial surge of power. With a rush of air, he was on the other side of the room, right on the tile he'd been looking at. As his eye faded back to normal, a bright grin spread on his face.

"See! _See!_ It's like nothing now!" His eye glowed again, and he was over at the work table. "Want your tea? I'll get it." He grabbed the mug with a giddy laugh before teleporting back to Gaster's side. "Here you are. I could go get some Crab Apples from Gearson, too, I'll just pop over and—"

"Sans, _stop._ " Gaster set the mug down to rub his forehead. "I understand that this is…that it is…" He grimaced, hand waving but unable to sign the word with his other hand occupied.

"Exciting? Amazing? _Life-changing_?" Sans hopped up on a nearby stool, grinning from ear-to-ear (metaphorically). "Gaster, I have it under control now! This means I can go anywhere in _no time at all!_ I can teleport into work, I can be here, I-I…"

" _Sans._ " The other skeleton's voice was uncharacteristically sharp, which shut Sans up. Gaster let out a huff and paced the short length of the table beside him. "I understand. I _do._ But you must think _logically._ " He flipped through his notes. "This ability…I can only think that it comes from your body's instability after your reset. If this is the case, then shifting around like this may be damaging."

Sans shook his head. "But we've been testing this for _weeks_ now, Gaster. I think we'd know by now if it were hurting me."

Gaster grunted, grabbing his mug and finishing the last dregs of his tea as he looked at the notes. "What about your innate powers? Have those been affected?"

Sans shifted in his seat. "Uh…kind of."

Gaster looked up, sockets wide. " _Kind of?_ Why did you not tell me?"

"Well, I just found out about it. Here, throw something at me."

Gaster frowned, then threw his empty mug at the smaller skeleton. Sans' eye flashed blue as he caught it in the air, then flashed yellow as he teleported it to the other end of the room. He repeated this several times, moving the mug faster and faster around the room, until his eye nearly looked green from how quickly the light flashed in it. Eventually, he brought it back and let it drop into his hands. He gave a small smile as he handed it back to Gaster. "So, uh, it's not just myself I can teleport."

The scientist stared at him, sockets wide. "How…interesting," he finally said, looking down at the mug. "How did you find this out?"

"Uh, sparring with Papyrus, actually."

"My god! Is he all right?"

"Oh, yeah, he's fine. He's actually pretty strong." Sans laughed. "He just assumed I'd been going easy on him for years."

Gaster looked at him for a long moment. He shook his head and finally smiled a bit as he sat on the stool beside Sans. "You know, I can tell the reset has affected you," he said quietly. "You are much different than when we first met. Not as…" His hands fluttered out the second half, "tense as you were all those months ago."

Sans half-smiled. "Well, part of that is the teleporting; cuts my transit time down to nothing, y'know. And I did what I wanted to do with my reset." He chuckled. "I knew I was missing a lot of time with Pap, but I didn't know just _how much_ I didn't know about him. Get this, he's started calling himself 'the Great Papyrus' all the time. It's awesome. And he tells me all about how he'll be the best fighter in the Royal Guard after Undyne. And god, the _puzzles!_ He makes so many!" He smiled warmly. "He's the _coolest._ "

Gaster smiled gently. "Well. At the very least, I cannot fault you for your motives. Perhaps one day I will be able to meet him." He looked up at the clock. "I suppose I have kept you long enough for now. I should let you go to see your, er, 'cool' brother."

Sans grinned. "I'll see you around, Gaster." There was a whoosh of air, and the seat was empty. As Gaster stood up, there was another whoosh, and Sans was back, another big grin on his face. "By the way, a week from today's gonna be a big day. Just sayin'."

One final whoosh, and he was gone.

* * *

The "big day" was, naturally, the end of the research. Sans had spent the whole week practically vibrating with excitement. He'd managed to keep his secret—despite his frustration at seeing everyone come up with wrong theories—for the past couple months, but these last few days were absolute _torture._

But the day finally arrived, albeit with a terrible commotion from downstairs. The first crash was what woke Sans up, but the sound of bones clattering sent him barreling out of the room. "Papyrus!"

He ran down to the kitchen as fast as he could. Had something gotten inside? He stopped dead in the kitchen as he saw that, yes, something had. A Whimsun apparently got in through the window, and Papyrus had clearly engaged in a very furious battle, given how he was monologuing at it.

"And I, the Great Papyrus, will be willing to spare you, but if you refuse I shall have no choice but to use my SPECIAL ATTACK!"

Sans grinned, sitting at the table to watch, though he frowned curiously as he noticed the bottom drawer—the one designated for their bones—was slightly open. Was that a tail?

The poor Whimsun, meanwhile, was hyperventilating too hard for it to leave.

"You leave me no choice!" Very slowly, as if expecting the Whimsun to attack, Papyrus leaned down and opened the bottom drawer. There was a little bark, and a white dog bounded out and skittered out of the house. " _Again?_ "

Sans laughed. "Looks like you'll have to _bow-wow-_ t, Pap."

" _Sans!_ "

All of this was far too much for the poor Whimsun, who flew back out the window, crying hysterically. Papyrus turned and frowned at his brother, who shrugged.

"Hey, that counts as a win."

" _You_ were no help at all! Have you _always_ been this lazy?" He waved his hand at the window. "We had a threat at hand!"

Sans grinned. "I thought you did really well. You were _doggone_ great, actually."

" _SANS!_ "

He jumped down with his seat with a laugh. "Okay, okay, I'm done. I promise. I need to get going, anyway." As he walked out of the room, he stopped. "And, uh, take it easy when you're out with Undyne today. You had a _ruff_ morning." He teleported away with a laugh, but not before hearing Papyrus' wordless scream of annoyance. And to think, he'd been too busy working last time around to really enjoy Papyrus' hatred of puns.

* * *

Through some spectacular willpower, Sans managed to get through most of the research session without saying anything. He greeted and contributed, yes, but he didn't mention his reset, not yet. He had to wait for the right moment. He had to make sure everyone knew their theory was correct. This time around, it was Terrin who read out their final theory; he had done it last time, but the anticipation left him unable to say anything.

"All right, everyone, so here's our conclusion…" She was bouncing in excitement. "Since humans are made up of mostly water, they can flow between timelines with the large amount of magic down here. But, it is likely possible that a monster _could_ force their own magic and dust to float to another timeline. _But_ no monster would, because it would…"

"I did it."

It came out a lot softer than he'd anticipated; he'd expected to be shouting about his success now that he could. But after months of keeping his secret, it felt almost… _wrong_ to reveal it now. Nonetheless, every eye in the lab was on him. Terrin lowered the paper she had been reading from.

"What?"

Sans swallowed, then gave everyone a nervous smile. "I did it. I reset." His voice shook as he stood up. "It was…well, it's hard to explain, but it was, uh, tonight? We'd gotten to this point, a-and then that night, I focused on letting myself, uh, get to another timeline…or maybe just back in time, I haven't figured that out yet. So I ended up going back to when we started the group." He grinned. "But I _did it_. And I'm fine! Monsters can do it!"

There was a stunned silence, then Sans was immediately barraged with questions.

"Did it hurt?"

"Was this timeline any different? Or was it, like, time travel?"

"So _that's_ why your answers were always right!"

"Did you have to fight yourself?"

"Why would you do something so _dangerous,_ Sans?"

"You are leaving something out." The group went silent as Gaster spoke. He looked up at the other skeleton. "You did not mention the, ah, _side-effect._ "

" _Side-effect_?"

"Oh my god, Sans, _what happened?_ "

"Are you okay?"

Sans held up his hands. "Okay, okay, everyone calm down. It's nothing dangerous or harmful. It just, uh…" He grinned, then teleported to the other side of the room. "Let's just say I know a lot of shortcuts now."

Another silence. And then the room was absolute chaos. There were congratulations, shouts about how they could _all_ reset now, frantic rustlings of paper to see if this was really possible or if Sans was just pranking them. Sans glowed with pride; he _was_ the first to do this, after all. His expression dimmed, though, as he caught Gaster's worried look. He cleared his throat.

"Uh, hey guys, _guys!_ "

Once again, all eyes were on him. He looked around the room at each of his colleagues.

"Uh…I mean, it's not something we should _abuse_ , y'know? The teleporting…I mean, it's _really cool_ , but…it's, uh, probably not good in the long run? I don't know. I haven't really had the resources to look into it."

"But I have." Everyone turned as Gaster spoke again. "I…still have quite a few unanswered questions, but I have been doing research during my off-hours to find out why you were affected in this way. The, er, teleporting, as you are all calling it, is likely a result of the dust you have lost during your reset, not to mention whatever comes with altering time." He let out a breath, looking at the group. "But…I am afraid this does change our theory. Monsters _are_ able to reset, but we do not know what the implications of this are. So…I propose continuing the research." His browbone furrowed. "But we _must_ exercise _extreme caution._ Time is a delicate thing, as are we. I…cannot forbid you from resetting, but please, only _once_ if you must. If Sans is slightly unstable after one, I cannot imagine what more would do." He glanced at the clock on the wall. "But for now, let us break." He smiled a bit. "I am certain that you all have plenty of questions, and I am not one to discourage questioning." He gave a little wave toward Sans. "As you were."

The group turned back and began hounding Sans again.

"Hang on, hang on! Let a skeleton breathe!" he laughed. "Tell you what, let's head to Grillby's and I'll tell you guys everything." He winked. "Race you all there," he said, then teleported away.

Grillby's was quiet—for now, anyway, he'd have to leave Grillby a big tip after the Q and A session—and he had a moment to think. Things had been nice for the past couple months. He had known what big things would happen, which meant he'd been prepared. There were some little variations from the first time he'd lived through these past months, obviously: more time with Papyrus, more conversations and lessons with Gaster, less worry from his job. But overall, nothing had surprised him since he'd done it before. Now though…now he was going into uncharted territory.

And, if he was being honest with himself, he was more than a little worried about all the possibilities. There was still that _thing_ that launched all this research, and the humans, and a whole host of other potential problems.

But, as he heard the research group come through the door, he relaxed. Twice in a row things had been good. Maybe, if he was lucky, things would keep being good.

A skeleton could hope, right?


	8. Sorry

With the new revelation that monsters _could_ reset, the researchers were all in a flurry to collect as much information as they could. Sans laid out everything he had done in the plainest terms he could, and he and the other seven researchers discussed the possibilities and results.

"So, like, I didn't _feel_ anything when you reset," Ceris said, fiddling with her camera strap. "But I guess I wouldn't, right?"

"Come to think of it, that day _did_ seem a little weird," Tephra added with a frown. "When we all met."

" _Or_ you're just _remembering_ it as weird," Wynn pointed out. "Because now you know that Sans reset."

"But it was like we all already knew each other!"

" _Might_ have been my fault," Sans said with a shrug. "I mean, I _did_ know all of you, and, uh, I wasn't that great at pretending I didn't."

Terrin glanced around, then leaned in to whisper, "Hey, Gaster isn't here, right?"

Sans shook his head. "He said there was an issue with the other experiment, the one he's doing with his assistant."

Her fins perked up. "So tell us what the differences are between the first timeline and this one."

Everyone leaned in expectantly, and Sans rubbed his top vertebrae. "Uh, well…I went to Grillby's with you guys a lot more?" He shrugged. "Other than that, it's really been the same. I didn't change anything drastic. I mean, there's the teleporting, but that's it. And I only went back about two months."

Terrin tapped her lips. "So…for us to _really_ know what could happen, more than one of us needs to reset." She sat up straight. "And take notes of what happened!"

"But we can't do it all at once!" Ceris added. "Because, like, that will _really_ screw up the timelines. But if we all do it, just _once…_ "

"We'll have tons of data!" Wode, a small dinosaur, added brightly. Wynn frowned and shifted.

"But Gaster said we should _only_ do it if it's a necessity," he said. Terrin grinned.

"So we don't _tell_ him." She pointed at Sans. "And _you_ don't tell him, either!"

"What?"

"We all know you guys talk all the time, but this time you _need_ to keep quiet. Otherwise, there'll be no way for us to compare our experiences."

Sans grimaced. This…was not what he had planned for this discussion. But they did have a point. They needed more data. He huffed.

"All right, I'll keep quiet. But if _anything_ goes wrong, we go stop and go straight to Gaster."

Terrin waved. "Fine, fine! We'll figure that out later. For now, we should make a schedule…"

* * *

Research continued over the next couple weeks. Every now and again, someone would show up with a bit of their tail missing or a little shorter than they were before, but always with a big smile on their face. Strangely, it seemed that only Sans and the other few who had reset could notice these things, though no one outside of the resetter could recall a reset actually happening. With Gaster out more and more frequently, either to the restricted Lab below or to Asgore, they were able to discuss the possibilities. Were those who reset more sensitive to these changes? Did messing with timelines put you outside of time? Soon enough, it was clear to Sans that it was time to let Gaster in on what was happening.

After they broke for the day, Sans waited in the lab for Gaster to return from below. One hour went by, then two…finally, the door to the restricted Lab opened, and Gaster walked out wearily, with a yellow, nervous-looking dinosaur following him.

"But, I _swear_ , with the first test subject, it was a…" she was saying, then stopped as she noticed Sans sitting on the stool. She broke into a sweat. "Oh…erm, hi…?"

Gaster looked up, and he sighed. "Have you been here for long?" he signed, hands moving slower than normal.

"No," Sans lied back. Gaster nodded, then gestured to the dinosaur.

"This is Alphys, my assistant," he introduced aloud. "She has been aiding me in the other, er, more official project I have been working on." He glanced down at Alphys. "Alphys, this is Sans. He is…"

Sans signed a quick "Do not tell". Just looking at Alphys told him she'd freak out if she heard his real job.

"…the head, I suppose, of the research we are doing into resets."

Sans smiled, then walked over and held out his hand to shake. "Nice to meet ya."

Alphys managed a painful-looking smile as she limply took Sans' hand. "Uh…same." She glanced between the two. "Er, um, maybe…we could talk about this…later?"

"I think that is best, yes," Gaster agreed. "Go home and rest. It has been a trying day."

Alphys nodded, gave Sans an awkward "bye", then headed out the door. Gaster watched her for a moment, then practically dropped into a chair, covering his face. Sans shifted his weight from one foot to another.

"So, uh, rough day?"

Gaster gave a wry smile. "To…what is the phrase? To put it lightly." He sighed. "I do not think I can manage a lesson today, Sans."

"No, no, that's not why I'm here." Sans' browbone furrowed as he sat down. Maybe now wasn't a good time to bring up the resets. "Uh, so what happened?"

Gaster huffed, looking up. "I am afraid I cannot divulge the details. It is strictly between Asgore, Alphys, and myself. But…well. It is a containable problem, but not an easily fixable one." He looked over at Sans. "Have you heard of Determination?"

Sans shook his head.

"It is…well, it is difficult to explain. It is a trait widely found in humans; it is, in its simplest definition, what enables them to continue fighting rather than retreating. But we have found certain monsters—well, one, at the moment, though I have my theories on others—who possess it as well." He shook his head with a sigh, shutting his sockets. "Perhaps I will explain more another time, but for now, I am very tired."

"I can…I can go, if you want."

"No, no, it is quite all right. Tell me why you are here."

Sans looked down again. "I, uh…I just wanted to talk. Y'know. About what things were like above ground." He smiled weakly. "Maybe try out a few jokes on you; Pap can't seem to see how _humerus_ I am."

Gaster chuckled, then sighed. "You know, I have not had the chance to say it, but I am very glad that your reset was a success. It has been a long time since I have had such a…an amiable companion…"

"You could just say friend, you know."

"Yes, yes, I suppose I could. It has been a long time since I have had a friend, and it would be a terrible thing if you had dissolved… _tibia_ -nest." He cracked a socket open with a smile as Sans let out a loud laugh. "Where would I have learned this language's wordplay?" He sat up. "Now, you said you wanted to hear more about above?"

* * *

A week went by. The six other researchers carried on as normal, Gaster was still absent with his other project, and Sans continued keeping the secret. He had gone from part-time to on-call with Asgore and Papyrus had been _sort of_ accepted to the Royal Guard as a part-time patroller, no doubt to keep him from bothering Undyne as much about being brought in.

Today was no different, save for the fact that Gaster was actually with them. However, their discussion was violently interrupted by the sound of metal crushing against metal. Everyone jumped back as the doors to the lab were kicked in, and a heap of armor burst into the room, gasping out, " _Sans!_ "

"Undyne?" Sans stepped forward with a frown as Undyne tore off her helmet, breathing hard. "Quick, someone get her water!" he ordered, then turned back to her. "What is it? Is there a human?" That would be the only reason they would speak, but normally she'd go to Asgore first. What could be wrong?

Undyne shook her head as Wode brought over some water, and her one eye blinked very quickly. Was she…fighting tears? That would be the last thing she would fight. She took a deep breath, getting herself together enough to wheeze out, "I…I sent him to the wishing room. I thought…" Her voice broke. "I mean, nothing ever happens there!"

A chill ran down Sans' spine. "Who did you send?"

Undyne swallowed. "He just…he wanted to patrol _so bad_ …"

" _Who_ did you _send_ , Undyne?"

She was silent for a long moment, then held up the plastic bottle she had been holding, filled with white dust.

"I…I got what I could."

Everything came to a grinding halt. Sans felt his chest constrict as he stared at the bottle, brain full of static as his hands mechanically took it. Gaster said something to him; he could almost hear Undyne punch a wall. But none of this was registering.

Something had killed his baby brother.

The static grew louder, to where the only other thing he could hear was his breathing, getting harder and harder the longer he stood. A fluttering hand settled on his shoulder, but he savagely shrugged it off.

With a small rush of wind, he was gone.

* * *

The wishing room was disgustingly peaceful. There were soft murmurs from the echo flowers, and the crystals shone brightly overhead. Sans held the bottle close as he appeared in the room, the plastic crinkling loudly. This was where his brother had died. Somewhere that was supposed to be _safe_ for monsters. He drew in a jagged breath as his eyes locked on the bits of white dust up ahead, illuminated brightly by the crystals' light. His legs wobbled as he took a step forward, but he froze as he heard Papyrus' voice.

"Wowie! A talking flower!"

His head turned to the source, hoping that _maybe, possibly…_ but no. It was just an echo flower, repeating the same line over and over. Had they recorded all of Papyrus' last few moments? With a sick curiosity, he walked up to the next one. He needed to know what happened.

"Well, golly, are you a member of Royal Guard? You sure look like you are!"

Despite the cheery tone of the voice, a sick feeling coursed through Sans. He _knew_ that voice, he knew that it belonged to something…terrible. But where had he heard it before? He pushed himself forward to the next flower.

"I am! Well, sort of! I'm in training; that's why I'm patrolling!"

Sans took a shaking breath, feeling the bottom of his sockets grow wet. _God_ , why was Papyrus so _trusting_? Why hadn't he seen that this thing was _bad_? He held the bottle as close as he could, plastic pressing against his ribs as he walked.

"Well, gee, maybe I could help you train? I'm _sure_ you have a great special attack! But go easy on me; I'm just a flower!"

 _God_ , that voice! Sans got away from it as fast as he could. The next flower was a ways off; each step made his chest tighter and tighter. When he finally got to it, it was a cacophony of shots and bones clattering. He could just barely make out the two voices in the repetitions.

"Wait, what are you—"

"You're such an IDIOT!"

Finally, he pushed himself to the last bit of dust, trying to keep himself from collapsing in front of the final flower. The static was back, and he could just barely hear what it whispered.

"You weren't as fun as your garbage brother."

Sans was trembling hard; he could barely keep his hold on the bottle. It took several minutes before he could even force his brain to think. When he did, one word kept repeating.

 _No._

No, no, no, no, _no._

Papyrus _couldn't_ be dead! Not now! Not when he had _just_ gotten the chance to get to know him! A whimper escaped him as he practically hugged the bottle. He needed his brother back. _Nothing_ would matter if he was gone.

But…

There was a way.

He just needed to—

" _Sans!_ "

A breathless voice stopped him mid-thought, and soon all the echo flowers were repeating his name. Sans turned to see Gaster, out of breath, trousers and lab coat soaked to the knee, standing at the opening of the room. As he regained his breath, he began signing frantically.

"Sans, Sans, I realize this is painful. But you _must not_ do anything rash!" He looked up with a pleading expression. Sans remained silent, hands still wrapped tightly around the bottle. He continued, speaking aloud but signing the words he couldn't immediately think of. "We have already seen the effects of resetting. I know…I know you think your teleporting is an improvement but there is a very large possibility that another reset will be damaging! You may even dissolve!"

Sans' mouth twitched, and he adjusted his hold on the bottle. They both knew what he was about to do. Gaster shook his head.

"Do not be _selfish_ , Sans!" he pleaded. "So many things could go wrong if you dissolve! Think of how the timelines will be affected! There will be no way to continue the research! We will not be able to stop whatever is causing the resets!" The scientist fell silent, jaw trembling as he locked his sockets with Sans'. His voice grew soft and hoarse, and his fingers fluttered weakly. "Please, Sans. Please do not leave me to be the last of our kind."

Sans blinked, two tears finally spilling over his cheekbones. He set the bottle down with a shuddering breath, then met Gaster's gaze as he held up his hands to sign one thing.

"I'm sorry."

"No, _no, Sa—_ "


	9. Changes

Sans bolted straight up with a gasp. His bones ached, and he felt sick, but that didn't matter. He pushed himself out of bed, ignoring the nausea and weakness. He had to make sure this had worked. He froze as he heard a crash and a clatter of bones.

" _Papyrus!_ "

He ran down the stairs as fast as he could, nearly stumbling as his head swam. Could skeletons throw up? He hadn't thought about it, but now wasn't the time.

"Pap-Papyrus, I'm co…" He trailed off as he reached the kitchen, finding Papyrus mid-monologue.

"And I, the Great Papyrus, will be willing to spare you, but if you refuse I shall have to—"

" _Papyrus!_ " Sans gripped the doorway, his sockets wide. Oh god, oh _god,_ it had worked! His face split into the widest smile he'd ever worn, and he more or less launched himself at his brother, hugging him tight enough to send a few pops through Papyrus' spine.

"Ouch!" Papyrus frowned down at Sans, and he freed one of his arms to wave at the whimpering Whimsun. "Sans, this isn't the time for horseplay! There is a _threat_ in our _house!_ "

Sans laughed and forced himself to let Papyrus go. He wiped at his sockets, once again wet but this time with relief. "Oh my god…oh my god, I'm so glad you're all right."

"I-I appreciate your concern, Sans, but…it's not really _that much_ of a threat," Papyrus said. He looked down at Sans, slightly concerned. "Are you all right?"

"Yes! I am…I am doing _so good._ Everything is _great!_ " He let out a breath and shook his head. "Okay, yeah. So you're about to fight the Whimsun, right?" He looked up at Papyrus, whose sockets were narrowed as he looked at him. "Pap?"

"Sans, there's something…weird about your face."

Sans' smile fell. "Weird? Weird like what?"

"It's…" Papyrus' odd look faded, and he poked Sans' cheekbone. "It's lazy, like the rest of you! I told you, there's a _threat_ in our _house,_ and I, the Great Papyrus, will not allow it any longer!"

Sans laughed. "The Great Papyrus can definitely handle it. And uh, you might want to check the bone drawer before you start the fight. I don't want you to be _howling_ mad." He backed out of the kitchen and stopped halfway up the stairs as he heard " _Again?"_ and, a moment later, " _SANS!_ " as Papyrus got the joke.

God, _god_ , he had never been so relieved. Papyrus was alive. It had _so_ been worth the risk. He'd be careful this time. Tell Papyrus to keep his guard up, no matter _what_. Keep an eye on him when _that day_ rolled around.

He sighed contently as he reached his room. Today, he remembered, was where he revealed his reset…well, the first one. But maybe he could skip it…he'd much rather spend as much time as he could with his brother. He rubbed his skull as he walked over to his dresser.

"So…be faithful to the timeline or spend the day with Papyrus?" he asked himself, looking up at his reflection. "What do y—" He stopped, sucking in a sharp breath.

Beneath shocked eye sockets, his mouth was stuck in a wide grin.

"What? _What_?" He spoke aloud more to see if his mouth moved, but it stayed firmly stuck. He tried to open it, to close it, to frown…eventually he even grabbed his lower jaw and tried to push it closed, but no luck. His face was frozen from the nasal cavity down.

He gripped his skull, trying not to freak out too loudly. Okay. Okay. This was probably a side-effect of the reset. It still _felt_ like it was moving when he spoke though. Did it just look like this? Would he still be able to eat? Was this some sort of glitch from not having enough dust? His chest tightened as the questions kept piling on top of each other in his mind. He needed to get to Gaster, str—

" _Do not be_ selfish _, Sans!_ "

His thoughts stopped for a moment, and let out a slow breath as Gaster's words repeated in his head. Selfish. He'd called Sans selfish. For what? Trying to _save his brother_? What kind of cold-hearted son of a bitch _said that_ , anyway?

In the mirror, Sans caught his reflection sort of grimace—as close as he could manage with his face frozen, at any rate. In any case, the thought of meeting with the other skeleton to discuss this—or _anything_ —left a bad taste in his mouth now. He'd been studying resets long enough now to figure this out on his own.

He didn't need the help of someone who thought looking out for family was _selfish._

* * *

Sans did finally go to the lab, though he found himself dozing half the time and nearly missed his cue to make the announcement. The reaction was strange, too; half the group was shocked, the others merely nodded knowingly, though they did ask about why Sans' face was frozen. The other half merely assumed it had always been that way.

It was fairly clear that the timelines had been, frankly put, pretty fucked up, though Sans was certain that wasn't all his fault. Six people resetting at various times meant that none of them had a coherent past up until the meetings began. This time around, research turned from learning how to reset to figuring out the effects of resetting, both on the monster and on how the timelines interacted.

Thankfully, Gaster had still been busy with whatever he and Alphys were working on downstairs, which meant that Sans hadn't needed to interact with him. Once their time was up, he was out, either to Grillby's or just back home to sleep. He was _always_ tired now, and his attacks weren't nearly as powerful as they used to be. _Papyrus_ had beaten him on occasion—not to say that Papyrus wasn't strong, but he also wasn't set up as the final defense before reaching Asgore. He kept quiet about this, obviously, and there wasn't anything he could do about it now, but…still. It added to his worries. By the week Papyrus was supposed to be killed rolled along, he was completely on edge, so much so that the whole research group kept their distance. Except for one person.

"Sans!"

"What?" The word came out as more of a snarl than he meant it to. He sighed and turned around. "Sorry, I…" He trailed off as he saw Gaster looking at him, face concerned. "Oh. Hi, Gaster."

"Is there something wrong, Sans?"

Sans quickly turned back around, half to cut the conversation short and half to hide his mouth. He wasn't sure if Gaster would notice, but he didn't want to risk it. "No. I'm fine."

"Well, I am sorry I have not been here lately. Things are, er…difficult in my other experiment." The other skeleton's tone turned hopeful. "But it is contained for now, so perhaps you could tell me what discoveries you all have made? Or we could have another lesson; your grammar improved quite a lot with the last lesson! Have you been practicing?"

Sans grimaced. He'd been keeping his hands in his pockets to _stop_ them from moving. As Gaster leaned over, he pulled up his hood. "Can't. Have to go home."

"Sans…are you _certain_ that you are all right?" A fluttering hand rested on Sans' shoulder, and he quickly shrugged it off.

"I'm _fine_ , Gaster," he said sharply, turning his head just enough to glare at the other skeleton, who looked completely dumbfounded and…hurt?...by Sans' reaction. He huffed, trying not to feel bad. After all, Gaster only cared about the science, didn't he? Not the monsters affected. He shook his head sharply. "Bye."

He teleported away before he lost his nerve and apologized.

* * *

 _That day_ finally arrived, and Sans didn't even pretend to have any qualms about changing things. Papyrus had to live, even if everything else was screwed up. Papyrus _had. to. live._

So, naturally, he was trying his best to get himself killed.

Sans had stayed home today with the express purpose of convincing Papyrus to skip his patrol, but he hadn't realized just how damn _addicted_ Papyrus was to working. If it weren't for the fact that his brother's life was on the line, he would have given up by now.

"Seriously, Pap, when was the last time we spent a _whole day_ together? I know you have the 1,000,000th MTT Episode Special taped, we could watch it together!"

"Sans, I appreciate that you finally understand the appeal of the MTT series, but Undyne needs me!" Papyrus looked at Sans with bright sockets. "I _know_ she'll promote me to full-time patroller soon, and then I'm _that_ much closer to the Royal Guard!"

Sans, for once, was glad his face was stuck; there would be no way he could hide his grimace at how much work this was turning out to be. "But where's the fun of a job if you can't play hooky now and again?"

"ALL the fun of a job is not playing hooky! I mean, the fun of not playing hooky is…I mean…I need to go!"

Sans broke out into a sweat, and he blurted, "What if I take you to meet Asgore?"

Papyrus froze at the door, then slowly turned his head, his brow bone furrowed curiously. "Meet… _Asgore_? The _king_ , Asgore? That one?"

Sans nodded, trying to keep his breathing even. Normally he'd joke, but if this was the key to making sure Papyrus made it, he was going to be as serious as possible. "Yeah. I mean, he _will_ technically be your boss when you get in the Royal Guard. Best make a good impression as soon as possible, right?"

Papyrus thought this over for a long moment—a _very_ long moment. Just as Sans thought he was about to dissolve right there from the tension, his brother's whole face brightened. "You're right! I can't waste this opportunity! I need to make sure the king knows that I'm _the best candidate_ for the Royal Guard!"

Sans let out a quick breath of relief, relaxing as Papyrus bounced in place. Thank _god._

 _"_ When do we go? How do we get there?" Papyrus asked excitedly. Sans laughed.

"Relax, I know a shortcut," he said, then frowned. "But, uh, you're gonna have to promise me one thing, okay?"

"Of course!"

"If a flower talks to you, you need to kill it. Hit it with your strongest attack right off the bat, don't give it time to say anything else. I need you to _promise_ me this, okay, Pap?"

Papyrus frowned. "That's…a very specific promise."

" _Please_ , Papyrus," Sans pleaded, gripping his brother's arm. Papyrus' browbone furrowed, but he nodded.

"Okay, I promise."

For the first time in the past few days, Sans' smile was genuine. "Okay, excellent. Now, that shortcut I was telling you about…"

* * *

They appeared in the hallway, and Sans kept his hold on Papyrus as they walked, more to keep him from smacking into any pillars as he looked around. It was weird, being here off-duty, and doubly weird with Papyrus. But he was distracted enough by how quickly Papyrus' head was swiveling around to take in everything.

"Careful, bro, your head might just come off if you keep looking around like that."

"But everything is _so cool!_ "

"Heh…" Sans took a moment to look around the hallway, something he hadn't done in a _very_ long time. "Guess it kinda is."

"Hey, wait." Papyrus' head stilled. "How do _you_ know Asgore?"

Sans shrugged with a wink. "I work a lot of jobs." That wasn't really a _lie_. "It gets you connections."

"Wow…"

They approached the door to the throne room, and Sans held up his hand to stop Papyrus. "Hang on, let me make sure he's not busy. This is, uh, kind of last minute, after all." He looked up at Papyrus for a moment, not wanting to leave him alone for even a minute. But he let out a breath and slipped into the room. As usual, the hulking monster in purple robes was watering his yellow flowers. He'd seen these flowers plenty of times, but for some reason they made Sans awfully uncomfortable this time around. He shook it off.

"Uh, hey, Asgore."

The king turned around, and his kind face lit up with a warm smile. "Sans! I'd started worrying Gaster's been using you for experiments," he said with a rumbling laugh as he set down the watering can. "I'm joking, obviously, he'd never do that." Asgore's face went stony suddenly. "There isn't a human, is there?"

"Like I'd let one get this far?" Sans asked, shaking off the mentions of Gaster. "No, uh, it's actually…well, if you're not too busy, my little brother would _really_ like to meet you."

Asgore's smile returned. "Of course!" He chuckled. "But if he's _your_ brother, I might be tempted to give him an interview right away."

"Heh, he'd actually love that. But, uh, actually…could you keep quiet about my job?" Sans rubbed his neck. "I, uh, I think it might worry him if he knew how dangerous it was."

Asgore pressed a furry finger to his lips with a smile. "Mum's the word."

Sans winked—it'd become his new smile, more or less—and went back to the hall. He just barely hid his relief as he saw that Papyrus was still there, all in one piece and slightly vibrating from excitement. "Come on in, Pap."

Papyrus followed Sans inside, head once again swiveling like mad to drink in the royal throne room. He froze, though, as his sockets locked on Asgore.

"Sans…is that…?" he whispered. Asgore chuckled.

"Howdy," he greeted, walking over and starting to hold his hand out to shake. Papyrus, however, immediately bent over double, his head nearly knocking into his knees.

"It is an HONOR, King Asgore, your highness, sir!"

Sans chuckled, sticking his hands in his pockets. "Asgore, this is my brother, Papyrus."

"Oh, so _this_ is Papyrus!" He smiled at Sans. "I should have known he'd be your brother."

Papyrus' head immediately shot up. "You've _heard_ of me?"

Asgore turned back to Papyrus with a grin. "My captain of the guard's mentioned you were one of the trainees. You have a lot of promise, she says."

"She _does_?!"

Sans settled back on his heels, watching contently as Papyrus eagerly drank in Asgore's combat tips. There. Papyrus survived, and it looked like he was having the best day of his life. He couldn't ask for anything better. The moment, however, was broken as the doors to the throne room flew open.

"Asgore! _Asgore!_ " Gaster's unmistakable voice echoed through the room as he ran in, stacks of papers fluttering in his mangled hands. "There is an issue with the experiments. Alphys and I have just…" He stopped dead in his tracks as he caught sight of the skeleton in the corner. "Sans?"

Sans would have scowled if he could have. "Hi, Gaster," he replied flatly, just as he had for the past week at the lab. A grimace flitted across Gaster's face at the cold greeting, and he turned back to Asgore. However, his expression brightened as he saw the other skeleton in the room. "Oh! You must be Papyrus!" He moved his papers around to free a hand, which he held out. "Sans has told me all about you!"

Papyrus blinked, then took Gaster's hand and shook it with a smile. "Wowie, another skeleton!"

"It is always good to meet another, is it not?"

Sans' hypothetical scowl would have intensified. This had to be an act. He knew how Gaster really felt.

The scientist shook his head with a smile. "Ah, I have not introduced myself, you must have no idea who this old man talking to you is. I am Dr. W.D. Gaster, the, er, Royal Scientist." He blinked, looking down at his papers. "Oh, god, that is right. I am sorry to cut this conversation short, Papyrus, but I must speak to Asgore." He glanced over at Sans, then back to Papyrus. "Alone, I am afraid." He smiled. "But I would like to have a proper meeting when things are, er, less…" He awkwardly signed with one hand.

"Complicated," Sans finished dully, not meeting Gaster's sockets. He took Papyrus' arm, more protectively this time. "C'mon, Pap."

"It was so nice to meet you, Papyrus," Asgore said warmly. "I hope to see you in the Royal Guard soon."

"Yes, me, too! I mean, it was nice meeting you! I mean…"

Sans chuckled. "All right, don't hurt yourself," he said as he guided him out, overhearing bits of a discussion about failed experiments before the door closed. They walked a ways in silence, and Sans sighed. "Sorry we had to leave so soon, bro," he apologized, sticking his hands back into his pockets. He glanced up, only to see that Papyrus was positively glowing.

"That was AMAZING! King Asgore is so _nice!_ I thought he would be more…well, I don't know what, but not so nice!" He looked down at Sans with a bright smile. "And your Gaster friend was nice, too!"

Sans shrugged. "I guess."

" _And_ he's a skeleton, like us! I didn't know there were more!"

"Well, Mom and Dad had to come from somewhere, right? Skeletons don't just appear out of _thin_ air."

Papyrus frowned. "Was that a pun?"

"Not a very good one."

" _None of them are good ones!_ "

Just in case he made a pun out of that, Papyrus took several long strides to keep ahead of Sans, who merely laughed as he followed him. However, his browbone furrowed as Papyrus stopped and turned back. "Sans?"

"What?"

For once, Papyrus looked somewhat sheepish. "Do you…really talk about me? To other monsters?"

"Well, yeah."

"What kind of things do you…normally tell them?"

"That's a dumb question. I tell them how cool you are, obviously."

Papyrus cautiously brightened. "Really?"

"Come on, Pap, do I look like the kind of guy to _fib_ -ula?"

" _No._ "

"I know! You can see right through me!"

"YOU MADE THIS TERRIBLE!"

Sans laughed as he took Papyrus' arm. "Come on, don't _skull-_ k." He waited for Papyrus to finish his groan/scream of annoyance. "C'mon. If we take a shortcut, we can still watch the MTT special before dinner."


	10. Consequences

Things at home were infinitely better due to the simple fact that Papyrus survived _that day._ But…things seemed to only be getting worse at the research lab. By this point, everyone in the group of five had reset, and the effects were becoming obvious. As far as Sans knew, he was the only one who had reset twice, but the others seemed as lethargic as he was after only one. There also seemed to be…much fewer monsters than he thought they had started with, but for the life of him he couldn't remember who the others had been. Maybe they had dropped out from the stress of the work.

He still wasn't on speaking terms with Gaster. Maybe he wouldn't ever be. But the research needed him, and, quite frankly, he was still just as desperate for information on resets as he had been when this whole mess had started.

But…not much work was getting done today, admittedly. Sans, exhausted as anything, kept dozing off against his notes. He sat up straight as he heard a soft voice.

"Sans?"

His head shot toward the source, then he relaxed. "Oh, hey, Terrin," he greeted easily, though his brow furrowed as he looked the fish-girl over. "You, uh, you all right? You look a little _green around the gills_."

She managed a weak smile. "I just…wanted to talk." She gestured at the poorly-drawn doodles on his notes. "You, um, didn't seem all that busy."

"Heh, guess not. So what's up?"

She half-smiled. "God, it was so much easier last time…"

"Last ti-"

"Look, I have…I have a _massive_ crush on you. And, um…" She swayed slightly on her seat. "Wow, sorry, I am…really tired…"

"Did you reset? Again?" Sans asked quickly, catching her arm to keep her steady. She looked up at the ceiling.

"I was just…I mean, you said yes last time…well, you actually said 'sure, why not,' but I…I said something stupid about your brother and…and I just thought that I could…fix…" Her mouth went slack, and Sans jumped up to catch her as she fell out of the chair.

"Terrin? _Terrin,_ look at me!"

Her head lolled back, and the color drained from her face. Sans stared in horror as she began to _melt_ right out of his hands.

" _Gaster!_ " he cried out, looking around for the other skeleton and vaguely aware of the others' cries of horror as…whatever Terrin melted into seemed to seep out of existence. The elevator from the downstairs lab whirred, and Gaster threw himself out of it just as the last bits of Terrin seeped away.

"Write this down!" he barked out. " _Anyone!_ "

"We ha—"

" _Write this down!_ "

Sans remained frozen for a moment, but he finally forced himself to move enough to grab a pen and scrawl out, "Terrin gone, melted, reset?" over his notes.

He turned back to look at the others. Why was he breathing so hard? The others were looking at each other blankly, and Ceris held her head.

"Did, uh, did something happen?" she asked, breaking the room's silence. Wynn scratched his ear aimlessly.

"Maybe there was another reset?" he suggested. "Is it like déjà vu?"

Ceris shook her head. "No, it's…I dunno. It was something scary."

Sans merely sat in silence. What had happened? Why did he feel so sick? He hadn't felt this shaken up since before his last reset. He didn't even shift away as Gaster walked over to his table and picked up his notes. The scientist frowned.

"Terrin gone…melted…reset," he murmured. Sans glanced up at him; that was more disjointed than usual.

"Hey, yeah, whatever happened to Terrin? She was…I mean, she was pretty cool, right?" Ceris asked.

Gaster sucked in a breath, sockets widening. "No…no, no, no…This is what I feared." He ran over to his desk, digging around in the drawers. Eventually, he pulled out a picture and beckoned the group over.

"Please, everyone, look." He held up the photo. It was the one Ceris had taken of their first day in the lab. He tapped on one monster's face. "Can anyone tell me his name?"

Silence.

Gaster tapped another monster's face. "Or hers?"

"That's, uh…that's Lonn…I think?" Tephra said with a shrug.

"No, no, that's, um…Suzy?" Ceris tried.

Gaster sighed, setting the picture down. "And now Terrin." He looked down at Sans' notes and shook his head. "This confirms what I had been afraid of. We all know that working with time is difficult on our bodies, and repeated resets are…more than deadly. It…I am not entirely sure, but I can hypothesize that you essentially are…erased out of time." He pressed his hand to his browbone. "Please, do _not_ reset again. Unless…unless it is for the sake of the Underground, it is _not worth the risk_." He let out a sharp breath. "We are ending the session today. I must go try and find…" He glanced at the notes again. "Terrin's family."

Gaster abruptly left the lab, and the three other researchers wandered out afterward. Sans, however, couldn't bring himself to move. Terrin, whoever she had been, had apparently just… _faded_ from existence altogether. That was _impossible._ He had to remember it somehow.

He couldn't just _forget._

* * *

He must have sat there for hours, wracking his brain for any trace of Terrin, but with no luck. Eventually, he gripped his head and let out a frustrated grunt.

"Sans?"

He sat up quickly, hands still on his skull. Gaster's browbone furrowed.

"I did not expect you to still be here."

Sans shook his head and let out a quick breath. Finally, he yielded to his need to talk. "I should remember what happened, but I…I _can't!_ She disappeared and I saw it and I _know_ it had something to do with me. But I-I can't even remember what she _looked like!_ "

Gaster set his hands on Sans' shoulders. "I realize that this is difficult to…er, process," he said softly. "But we _must_ press on. The resear—"

Sans grunted again, pulling away from the other skeleton and whirling around to face him. " _God!_ Do you care about _anyone_?"

Gaster stared at Sans with wide sockets. "Sans, I—"

"It's always the…the process, the research, the timelines! You don't care who gets hurt!"

The scientist looked as though he'd been slapped across the face. His hands fluttered, but they didn't quite make a word. Sans glared at him, ribcage heaving. Was he going to defend himself? Apologize? _Anything_? Sans' jaw trembled.

"You're as bad as the humans," he spat.

At that, Gaster's whole expression shifted into one Sans had never seen. His sockets were alight with fury, and his mouth twisted into an ugly frown. In two swift strides, he was in front of Sans, gripping his jaw hard enough to hurt.

"Do not _ever_ compare me to them!" he snapped, forcing Sans to look at him. "You have _no concept_ of what humans are, the horrible things they do!"

"I know they let others die just for their gain!" Sans snarled back, fighting against Gaster. Two resets ago he would have been able to break away, but the scientist was surprisingly strong. "Progress is all you care about! You can't even pretend sympathy when someone-"

" _You know nothing of the loss I have faced!_ " Sans recoiled as much as he could as Gaster shouted in his face. The scientist took several deep breaths, then narrowed his sockets. "You would like to know what it was like above ground? It was _hell._ I watched my people be _slaughtered_. My village was filled with their dust; it clung to me for _weeks!_ I come down here to spend centuries _alone,_ my language is _useless_ , but I adapt. I _survive._ And I am rewarded by finding the first skeleton in a thousand years, but I see now that he is no more than an _impudent child_ who has the gall to compare me to the _creatures_ that murdered my kind!" With a sharp breath, he pushed Sans away and turned his back on him. "Get out of my lab," he said coldly. "Do not come back."

Sans didn't move. His bones rattled slightly as he shook; he was furious, shocked, _overwhelmed._

Gaster glanced coolly over his shoulder. "Was I not _clear_?"

Sans didn't speak, merely sucked in several shaking breaths until his eye suddenly blazed blue. With a sharp cry, he shot several bones right at Gaster. The scientist merely flicked his wrist, and a wall of bones as tall as he was shielded him, leaving Sans' attack to clatter uselessly to the floor.

"Is this a sign that I am being judged?" Gaster asked dryly, swiping his hand to send the bones away. "You may as well tell me my sins."

It took Sans a long moment to speak. "You're a heartless liar," he said, voice shaking. "Yo-you pretend to care about other skeletons or the researchers, but when they die, you have _n-no idea_ what grief is. You say to 'press on' when someone's _erased_ from our memories. You…you ca—" Sans felt tears gather in the bottom of his sockets as he choked out, "You called me _selfish_ when I saved my brother!"

Gaster blinked, and his stony expression softened somewhat. "I…do not recall that."

"Papyrus died!" Sans cried out. "Some…some _thing_ killed him, and I ran out to the wishing room and I…" He sniffed. "I reset to save him. And you called me _selfish_ for that!" He shook his head. "I can't believe that you care about anyone if that's what you think about saving the only family I have."

Gaster watched the other skeleton for a long moment, and he finally shut his eyes. "You are very young," he said softly. "You are thinking in absolutes." He half-smiled. "And I cannot tell if I should be offended or flattered that you apparently used to hold such a high opinion of me that a mistake like this sent it crashing down." He sighed and dropped onto one of the nearby stools. "Am I allowed to plead my case?"

Sans didn't move, but his eye faded back to normal.

"I will take that as a yes." Gaster was silent for a long moment, his hands moving as he gathered his thoughts. "You see, just because I am a scientist does not mean I am always inclined toward rational decisions. I…cannot tell you what my motivations were in your last timeline, because it was not _me_ , strictly speaking, who said that. But...whatever my thought process was, I, in this timeline, would be with you in saying I was in the wrong." He sighed, suddenly looking quite brittle. "I do know loss, Sans. But my loss came with war. There was no time to mourn; I had to press on or risk being killed as well. Whatever has happened to the other researchers is a tragedy. But we mourn in different ways; I try to find the root of the problem, and you…well." He gestured to the bones scattered on the floor. He sighed again. "Perhaps this is not enough. Perhaps whatever the other me said is enough to ruin your view of me forever. I have said all I can."

Sans stood stock still, remaining silent as Gaster finished speaking. He was tempted to teleport out, but equally tempted to throw himself at the other skeleton like a kid, to tell him how sorry he was for treating him like this, how tired he constantly was, how… _terrified_ Terrin fading away and Papyrus' death left him.

"I…I have to go," he finally said, turning and pulling up his hood. He heard Gaster let out a small breath.

"I will not stop you," he said. "Though…this reset, it is your second, right?"

Sans swallowed. "Y-yeah."

"And I assume this is why your mouth has not moved?"

Sans didn't reply to this, instead pulling his hood tighter. So he _had_ noticed.

"Regardless of whether you associate with me or not, Sans, _please be careful_. I cannot stop you, but…" Gaster's voice caught. "I would not want to forget you. It would be like losing a—" He cleared his throat. "I am sorry. I will not keep you."

Sans kept his hold on his hood, standing there for a moment longer. Finally, he shook his head.

"Bye," he said simply, then teleported out.

* * *

He didn't return to the lab for a while. Really, he didn't do much of _anything_ for a while. Mainly he just laid on the couch, staring at the ceiling and trying to remember that Terrin person as well as sort out the fight he'd had with Gaster. This, naturally, earned him several chidings from Papyrus about the wrongs of being lazy. The first week, he was able to divert him with some jokes, but soon enough it was clear that even Papyrus wasn't being fooled. The lectures stopped.

God, he wished he'd just left all of this alone. If he could go back in time…well, no, that's what started this whole mess. But he resolved to himself then and there, no more resets. _Never_ _again._ He had obviously been lucky with the second one, even with all the troubles it had brought. He couldn't risk fading away from memory. Hell, he couldn't even remember how many had been in the research group; had they _all_ disappeared like that? How many monsters had met this fate?

He couldn't have given an exact number as to how many days he spent like this, but it was all brought to a halt as Papyrus dropped something onto his chest, waking him up from a doze.

"Jeez!" He sat up and rubbed his chest. "Give a guy a little warning before you _drop in_ like that, Pap."

Papyrus, for once, didn't react to the pun, instead shifting back and forth. "Sans, I've…noticed you haven't been doing much lately. And I thought it was your usual laziness, but then it just…kept going…"

 _Oh._ God, Sans didn't want to have this talk. "Papyrus, look, I—"

"So then I realized you must be bored!"

Sans blinked. "Uh…"

"Because you haven't been going to any of your jobs! And so I decided to fix it!" He gestured down to the thing he had dropped: a little badge with a delta rune on it. "So I've signed us _both_ up to be sentries in Snowdin!"

"Uh, gee, Pap, that's…"

"It's going to be GREAT!" Papyrus gushed. "I've been asking Undyne for weeks about taking it, but she kept getting… _weird_ about me patrolling alone. BUT, with the two of us, we can team up against any human that comes into Snowdin!" He bounced down onto the edge of the sofa, giddy with excitement. "And this way everyone's happy! You won't be bored, and I'll be closer to being in the Royal Guard!"

"Heh…" Well, this was…sweet. Sans sat up and pinned the badge to his hoodie. "You know, you're right. With both of us, _snow_ body's gonna get through to the rest of the Underground."

"Don't you…"

"What? I'm just saying _icy_ what you mean."

" _Sans!_ You're ruining things _again_!"

"I have no idea what the _hail_ you're talking about!" He chuckled as Papyrus promptly jumped up and started stomping away. "Hey, Papyrus, hang on!"

"I'm not speaking to you!"

"Thanks."

Papyrus turned around, and Sans…well, he couldn't _smile_ , but he looked at his brother warmly. "This really helps. I'm…I'm glad I've got you looking out for me."

Papyrus gave Sans a big smile. "Of course, brother!" He went quiet, browbone furrowed. "You could say…I've got your _backbone_."

Sans blinked, and his whole face brightened. "My god, Papyrus, you just made my whole day." "Don't expect it again! I, the Great Papyrus, do not stoop to _puns_ for entertainment." He bounced in place as he saw Sans get up. "Are you going to patrol right now? That's the spirit!"

Sans shook his head. "Nah, I've gotta go figure out my break schedule," he said with a wink. "Be back in a while." He headed out the door, then took a breath. He almost teleported, but decided he needed the time to think. If he was gonna move on past…what had happened, he needed to clear the air. The group should be meeting about now.

He reached the lab and stared at the door for nearly two minutes. He had to do it. Even if he wasn't going to reset again, he still needed to figure out what was happening with this _thing_ no one could remember. Maybe it was like what had happened to…well, whatever her name was.

He took a step forward, and the lab's doors hissed open. He frowned as he walked in; it was awfully dark. And far too quiet. He took cautious steps inside, looking around. "Gaster?" he called. "Hey, Gaster?" Had something happened to him? Sans felt something in him twist. Oh, god, what if he had reset and disappeared? No, he wouldn't remember Gaster if that was the case. But…what if that thing that had killed Papyrus…?

" _Gaster?"_

"Sans?"

He hadn't heard the door to the lower lab open, but regardless, Gaster stood in front of it, lit from behind by the elevator's light. Sans let out the breath he'd been holding. The old man was all right. Good.

"Why are you standing in the dark?" Gaster turned and flicked on a switch, lighting up the lab.

"I, uh, well, I didn't know…wait. Shouldn't the group be here now?"

Gaster looked at him for a moment, then sighed. "Ah. Yes, I had forgotten." He gestured to the empty lab. "This is all there is."

Sans's brow furrowed. "What do you mean?"

The scientist's shoulder sagged. "I mean they are gone. One day, I sat waiting, but…well, nobody came."

Sans' sockets widened. " _What?_ All of them? I mean, there were…there were, uh…" His face went blank. How many researchers had there been left? How many had there been to _begin with_? "Oh, _god_."

Gaster had walked over to his desk and pulled out a photo, the same one from Sans' last time in the lab. "Eight," he said quietly. "There were eight." He sighed and shook his head. "All I seem to create are catastrophic failures."

Sans blinked quickly. "But…the resets…"

"It is clearly too dangerous to pursue further research." Gaster put the photo into his lab coat's pocket, then rubbed his skull. "When we last spoke…you were right," he said softly, then gave a bitter laugh. "Your title is far more apt than I had realized."

Sans shook his head. "We…we can't just leave it there, though! The thing that was causing all the first batch of resets is still out there! If we can figure out what it is, we can…"

" _Sans._ It is over. I will not put anyone else in harm's way," Gaster said firmly. He glanced up, catching the pained look on the other skeleton's face. He shook his head with a huff. " _If_ I have any other ideas concerning resets, I will contact you. But for now…" He looked down at the floor. "For now, please spend time with your brother. He needs you far more than an old madman does." He looked up at Sans for a moment, then gave him a curt nod of dismissal. "It was…more than pleasant to work with you." He looked up, and his hands added, "And I wish you nothing but the best." Just as Sans raised his hands to sign back, Gaster quickly headed back to the elevator, door closing before Sans could sign even one word.

* * *

Surprisingly, the monotony of patrolling Snowdin seemed to be just what the doctor ordered. After all the stress of the resets, the loss, the fight with Gaster, a few months of walking around what had to be the least intimidating town in the Underground with Papyrus was, honestly, the best job he'd ever had. Sure, getting from the Core _all the way_ to Snowdin was a pain; he and Papyrus always went together, and while the occasional teleport with a plus-one was fine, a whole _week_ left him completely drained. Walking was the better, if more boring, option. But hey, Papyrus was having the time of his life. _Plus_ Grillby's was right smack in the middle of town. No one went with him now, but he managed to get friendly with a few of the other sentries. It almost made him feel like a regular guy. Things were good.

Even so, he'd be lying if he said that he wasn't a little excited when he saw the letter in his mailbox on his day off.

He recognized the symbols scrawled on the paper the moment he opened the envelope. To his surprise, he didn't even hesitate to translate them. Maybe the few months in Snowdin really had helped him _cool down._ His sockets widened as he finished the translation.

COME TO SNOWDIN IMMEDIATELY. WE ARE MAKING HISTORY. –G.

Well.

How could he turn down an invitation like that?


	11. Partner

**_AN: Sorry about the unannounced absence; I got hit with a TSUNAMI of school work and a work opportunity I couldn't pass up._**

* * *

It wasn't until he had teleported into Snowdin that Sans began to have second thoughts. After all, he and Gaster hadn't exactly left on the best terms. Plus there was the issue of _why_ he'd been called here; the scientist had said he'd only call him on reset-related business, and Sans had since sworn off anything to do with time.

He hesitated outside the town, debating. But eventually, curiosity won out. After all, he could always decline, right? He'd just…check things out.

He walked into the sleepy town, giving a few waves to the townsfolk that recognized him. Why would they go to _Snowdin_ of all places? After patrolling it for the past few months, Sans could guarantee that this was the _least_ exciting town in the Underground. Good for patrolling, yes, but it couldn't be that great for science. He kept a socket open for anything out of the ordinary, but it wasn't until he reached the large house on the edge of town that he saw the tall, thin figure waving an arm. Gaster was positively grinning at him; that was…weird, especially after everything that had happened the last time they'd spoken. The scientist quickly walked up to meet him.

"Sans! Forgive me, I should have specified the location, but I am _so glad_ you are here!"

Sans couldn't help chuckling; it'd been a long time since he'd seen Gaster so happy.

"Nice to see you, too, Gaster," he said, then glanced up at the house. His browbone furrowed slightly, and he pulled up his hands to sign, "What with house?"

Gaster looked at Sans quizzically, then mimicked the signs before shaking his head with a half-smile. "You are very much out of practice," he said, then turned and looked up at the house. "It _is_ quite…er, _much_ , is it not? Asgore insisted on something, er, _roomy_ , I think is the word? But it is much too big for my tastes."

Sans blinked. This was _Gaster's_ house? He must have passed it a hundred times by now. He glanced up at the other skeleton. "Y'know, I think it'd look better with some Christmas lights."

Gaster laughed. "And who would turn them on? I often spend my nights in the lab." He shook his head. "But this all is unimportant. Let us get out of the cold." He set a hand on Sans' shoulder and guided him into the house. Sans wasted no time in looking around; it certainly was roomy—much bigger than his and Papyrus' place in the Core—but…really empty. Gaster gestured to a nearby sofa, where a yellow dinosaur was sipping from a mug.

"Sans, this is my assistant, Alphys."

"We've already…" Oh, wait. Different timeline. "Uh, nice to meet you." He held out his hand for Alphys to shake. Alphys jumped up and took it with a sweaty palm, nearly spilling her tea.

"Hi! I'm A—wait, sorry, Gaster just said that." She gave him a pained smile. "Um, sorry I wasn't out there. I, erm, I don't do so well with the cold. Yo-you know, being, erm, cold-blooded. O-only physically, though! Not…oh, god, this is terrible."

"Hey, hey, don't worry," Sans assured, then winked. "Listen, when you're in Snowdin, you just gotta _chill_."

Alphys blinked, then gave a little snort. "Oh my god, that's awful!"

"It's only gonna get worse. I'm aw- _full_ of 'em."

She snorted again, and Sans chuckled as well as he sat down beside her. He looked up as Gaster re-entered the room, setting a steaming mug in front of the smaller skeleton. Sans looked up at him. "So, uh, why the note?"

Gaster grinned. "I made a discovery several months ago. You see, this house, though far too big, has the most fortuitous location." He pulled a small slip of paper out of his pocket, holding it up for Sans to see. Sans' brow furrowed as he took it.

"It's the picture of the research group," he said, brow furrowing more as he realized he couldn't name a single monster.

"Yes, yes. Now, look at this one."

Gaster handed Sans another photo. It was the same picture, but only half the group was in it.

" _What_?"

"You see, just below us is a room. Initially, I did not think anything of it and merely kept it as a storage room. _But then_ I saw this picture among my notes. It remained unchanged, as you can see." Gaster's hands were whirring in his excitement. "After the, er, _incident_ with Terrin, I brought down the second photo, to see if it was affected as well, and as you can see, it is frozen as well despite subsequent resets and, er, disappearances."

Sans leaned forward, brow furrowed. "So…you're saying your basement is outside of time?"

" _Yes!_ Well, at least, that is how it appears. I did some research upon realizing this; apparently there are rumors of a door in Waterfall that occasionally appears…" He shook his head. "I will be brief. Essentially, I have theorized that there are several of these 'grey rooms' throughout the Underground, but the one beneath my house appears to be the only one that is static!"

Sans leaned back. "And what does that have to do with 'making history'?"

Gaster grinned again. "If we have a place unaffected by resets, then that means we can work without fear of it all being erased." He shook his head, pacing excitedly as his hands flew too quickly for Sans to translate. "I have had an idea for a while, but it has been impossible to pursue what with the potential of a reset occurring. _But_ if the work can remain undisturbed, just as these pictures were, then that means that we can…that we can…" He blinked quickly, trying to find the words.

"We're gonna build a time machine!" Alphys blurted.

"A _what_?!"

Gaster nodded eagerly. "Yes! We know that resetting is dangerous for monsters. We are far too fragile to do it on our own without devastating side effects. _But_ if we could use a _machine_ to transport us across timelines, it would lessen the strain on our bodies."

Sans' brow furrowed, and he looked back down at the pictures. "This is impossible."

"Erm, not…not _entirely_ ," Alphys said. "I-I mean, there's no guarantee that it _would_ work. But…in theory…the machine would act as, um, as a container? Kind of? For a monster's dust. So…so they wouldn't lose as much."

"This is why we need you," Gaster said, meeting Sans' sockets, still grinning. "You are, for all intents and purposes, the leading expert on resets. You know what equations work and which theories are true. Your experience makes you much more knowledgeable than myself. And with Alphys' talent with mechanics…"

Alphys quickly shook her head, bright red. "It's not…I mean, it's just…"

"You do not need to be modest," Gaster said with a fond smile, then turned back to Sans. "You are familiar with the robot Mettaton?"

Sans chuckled. "He's all my brother watches."

Gaster proudly motioned to Alphys. "And here you are with his creator."

"Wait, really?"

Alphys had managed to turn a brighter shade of red. "He…uh…well, I mean…I-I did _make_ him…"

"Huh. Well, that's… _riveting._ "

Alphys covered her face with an awkward giggle. Gaster clapped his hands together.

"So! Are you willing to join?" the other skeleton asked, sockets bright.

Sans shifted in his seat. "Uh…well, I'll be honest. My last reset didn't leave me in great shape." He gestured to his permanent grin. "So, uh, I'm a little hesitant to do anything involving resets."

Gaster shook his head. "There will be no physical resetting, I promise you that. Simply equations until we can test the machine, which will not be for some time."

Alphys, fanning her face to cool it down, added, "That's true. It's…well, I mean, what we've _guessed_ is that we'll be able to enter the equation into a program, and the machine will do the actual reset."

Sans looked between the two of them, brow furrowed. It was still a risky move. Time wasn't something you could just _play_ with. But…if it was just equations…then he didn't have much to worry about until they built the actual machine. And, truth be told, he'd missed working in the lab and all the research. _Plus_ it was right where he and Papyrus patrolled…

He leaned back on the sofa. "So when do we start?"

* * *

Getting back into the scientific routine was… _outrageously_ satisfying. The equations, the discussions…with all the stress and worry from the past few months, Sans had forgotten how much he genuinely enjoyed doing research. And Alphys—once she'd been coaxed out of her shell—was good company. Sure, she was a little…okay, she was _really_ nerdy, but they spent plenty of time talking and joking between the grey room and the lab as they sorted out the time machine. It was like…well, what he imagined the research group must have been like. Except with a lot more gushing about anime.

Even with her obsession with big-eyed cat girls, there was no denying Alphys was a genius. After an idle comment that they should find a way to test shifting the equations into a program, she managed to put together a working machine to gauge shifts in the timeline.

"I-I mean, it's still really crude, a-and it's probably not guaranteed to work," Alphys said sheepishly as she showed the little machine to Sans. "But it's really no—"

"Okay, no, I'm gonna stop you right there," Sans interrupted. "This is _amazing._ We've needed something like this for ages, and you just whipped it up like nothing? You're definitely super cool."

Alphys went bright red and fidgeted. "Uh, um…thanks? I mean! God, I'm sorry, I don't take compliments well!"

Sans chuckled as he gathered up his notes. "Then how do you put up with Gaster? All I've heard about you is compliments."

Alphys managed an embarrassed smile. "He, uh, he tends to write them down. Then I don't have to react in the moment." She turned to fiddle a bit with the machine, then glanced back at Sans. "Hey, so…you, um, I mean, I heard you weren't really into science before the whole, um, reset thing."

Sans shook his head as he started making corrections. "Nope. More of a beat-'em-up kind of guy." He winked. "Then I got lazy."

Alphys smiled. "So, um, how do you know Gaster, then? If-If that's not too personal! But, erm, you know, he's kind of…reclusive? So…y'know…"

Sans looked up at her. Should he tell her the whole story? Well, probably not the Judge part—she was already so nervous, she'd probably dissolve right there if she knew what his real job was. He leaned back in his chair. "Well, uh, I live in the Core and do some… _free-lance_ stuff for Asgore. So I'd heard people talk about him. And everyone knows where the Lab is, so when I felt like something was off, I figured he was the best person to go to." He shrugged. "And the rest you know about."

"Oh, okay." She shook her head. "I thought you were, like, his nephew or something."

"Do you think all skeletons are related? Alphys, I'm _offended_ ," Sans teased.

"Oh my god! No! I'm sorry! I mean, there's the way he talks about you and you both do the hand signs, so I just thought…oh, god, I'm being skeletonist. Is that the word? Oh, god…"

Sans laughed. "Easy, Alph, it was just a joke. I asked him to teach me his language to, uh, get back to my roots, even though…well, it's all complicated. But I'm still pretty bad at it, mainly because I'm too lazy to practice." His brow furrowed. "Wait, you said he talks about me?"

Alphys nodded as she grabbed a wrench to fix a bit of the machine. "Well, yeah. I mean, it was mainly when you guys were doing the research, but he kept talking about all the theories you came up with and how exciting it was. So I thought, 'oh, he's a proud uncle' or something. But! That's dumb of me! Because you can talk about people all the time without being related to them! I mean, I talk about Undyne all the time and we're not related!"

Sans nodded, half-listening. Huh. He shouldn't have been surprised, really; it was just talk about theories.

Still…

Even with the issues over the past few months…

He couldn't say it wasn't nice to hear.


	12. Determination

"Sans? _Sans_?"

Sans jolted awake, lifting his head from the papers around him. He looked up, blinking a bit.

"Oh, hey, Alphys. Is Gaster here?"

Alphys shook her head. "Um, no, but…that's the second time you've dozed off today. Did you sleep last night?

Sans rested his cheekbone on his hand. "Barely. I only got ten hours."

Alphys frowned. "That's 'barely'?"

"I'm joking. And anyway, I do my best thinking when I sleep. I'm completely ar- _rest-_ ed with my hypotheses."

For once, Alphys didn't laugh. She merely looked at him for a moment, then returned to her work. Sans stretched before returning to his own equations. After a few minutes, though, she turned back to look at him again.

"Erm, can I…ask you something, Sans?"

"Alphys, I love you, but I'm not doing another Mew Mew Kissy Cutie marathon ever again."

"N-no…I just…" Alphys fiddled with her wrench. "Are you okay?"

Sans looked up in surprise. "What?"

"Are you okay? Like…physically?"

Sans looked at her for a moment, then sat back. Well, no, he wasn't. He'd been dead-tired ( _ha_ ) since his second reset, but with Judging, training, patrolling, and just _thinking_ , he was getting drained quicker than usual. Not to mention just how much… _weaker_ he was; it was a lucky thing Undyne had started training with Papyrus, there was no doubt his brother would be able to take him out fairly easily at this point.

But he couldn't just _say_ that. So instead he just winked and shrugged.

"All right, I'll be honest. I had a rough patrol last night."

Alphys leaned forward. "Really?"

"Yeah. We saw a rock that kind of looked like a human, so things were _pretty_ exciting in Snowdin."

"Sans, I'm _serious_. I mean, I get not wanting to talk about problems but…" She sighed, fiddling with her wrench again. "Okay, look, don't tell him I said this, but…Gaster's worried about you."

"What?" Sans laughed in disbelief. "He's definitely not. Whenever he comes over here, he's all about the work."

"Well, he's not going to _tell_ you. He doesn't do that." Alphys huffed. "I've worked with him for a long time, and so I can…kind of?...figure out when he's stressed out. Especially since I'm usually the one that's stressed out. A-and…" She shook her head with a sigh. "I-I know he'd rest a little easier if you got looked over. I-I could do it; we have a bunch of biology equipment in the lower lab from, erm, other experiments. And it won't be anything too bad! I built the machine myself, so I can promise that it's nothing too invasive."

"Heh, I'm not surprised." Sans took a breath, clicking his pen a few times. It probably _was_ a good idea to find out what all was up with his body after the resets. And…it _was_ kind of nice to hear that Gaster was worried about him. Maybe this timeline really was different. He set the pen down.

"All right, I'll come in tomorrow. One condition, though."

"What?"

"You don't get to talk about anime for a week."

Alphys groaned, and Sans laughed. This would be fine. How bad could a quick scan be?

* * *

Again, Sans had put his curiosity before anything else. After all, the scan would happen in the _lower_ lab, and that was a hell of an incentive for potentially finding out some troubling news. But really, the results couldn't be _that_ bad. Sure, he was tired all the time, and yeah, he couldn't move his mouth. But…that had to be the extent of the damage, right? Right.

There was the familiar hiss of hydraulics as he reached the main lab, but his brow furrowed once he stepped inside. It was…dark. And awfully quiet.

"Alphys?"

No answer. He flicked on the light switch, and the lab was most definitely empty. Maybe he was supposed to meet her downstairs? He felt a little twist of apprehension in his chest, but shook it off. The lower lab _seemed_ off-limits, but it wasn't like anyone had actually _said_ he couldn't go down there; and anyway, even if there _was_ a genuine ban on going to the lab, Alphys had invited him. This would be fine.

He walked over to the elevator and hit the button. Then he waited. And waited. It sure was taking a long time getting up to the main lab. Just how far down was the lower lab? He let out a breath as there was another hiss of hydraulics as the elevator doors opened, but hesitated on actually stepping in. There was something…awfully eerie about this whole thing, and he genuinely worried over whether this had been a bad idea.

But it was _Alphys_ who had told him to come. She was nerdy and more than a little anxious, but she wouldn't do anything _bad._ He sucked in a breath and stepped inside, pressing the button for the lower floor.

It was a long elevator.

Very long.

 _Too_ long.

Just as Sans thought it would keep going forever, it reached the bottom. He practically bolted out of the thing, then looked around. The lower lab actually…wasn't much better than the elevator ride. Strange whispery sounds echoed through the air, bouncing off the metal walls. And it was still _so dark._

"Alphys?"

No reply.

"Alphys, _seriously._ "

Still nothing.

" _Gaster?"_

Only the strange whir of machines greeted him. _God,_ where _were_ they? Sans swallowed hard, regretting this decision. Something was just so… _off_ about this place. But he couldn't back out now. He tensed as he walked into the next room, eyes scanning over the whole area as quickly as he could. He furrowed his brow as he saw it was full of beds.

"Heh…not even _I'm_ tired enough to try you guys out," he joked weakly, not liking the way his voice echoed back at him. But really, why were there beds in a lab? And why so _many_? He swallowed again and pushed onward.

"Alphys, would it _kill_ you to turn on some lights?" he called out, but still no answer. He stepped into the next room, then came to a dead stop. It was filled with…smoke? Mist? Whatever it was, he could barely see a foot in front of him. He reached his hand out to feel the wall as he walked forward. He stopped as he heard a strange, strangled noise, a chill running down his spine. Was something else here? He looked around, but the mist was too thick. His bones rattled as he continued walking forward. He felt along the wall a little more frantically to find some kind of light switch.

"Ha, got you." Too shaken to even joke to himself, he quickly flicked it on, hoping for _any_ kind of light. Instead, there was a loud whir of…fans? That wasn't what he wanted, but at least it cleared the mist. He turned around to retrace his steps, but jumped back with a loud cry of surprise as a large… _thing_ loomed in front of him. He'd never seen anything like it—there were so many legs…no face, just a gaping, black _hole_ …and the whole thing seemed to be _melting._ It took a lurching step toward Sans, and he jumped back, eye blazing blue.

"You take one more step and we're gonna have some trouble, buddy."

The thing cocked its head curiously, then wiggled its back half before bounding forward. The whole lab shook with the force of its jump, and Sans fell backward. He held up his hand with a huff.

"I warned you."

" _Stop!_ "

Sans looked up as Alphys ran into the room, panting hard as she threw herself between him and the _thing,_ arms up as if that would shield it more.

"Don't hurt them! They're not dangerous!"

Sans stared at her, then shook his head, eye still glowing. "Not…Alphys, _look_ at it! It could have killed me with one more jump!"

"N-no! I swear it wouldn't!"

Sans jumped up to his feet. "What the hell even is this anyway? What are you and Gaster _doing_ down here?"

Alphys cringed. "It…it's…" She swallowed. "It's…part of an…an experiment."

"And does _Asgore_ know about this? Or are you two just…just mad scientists working on…on horrors like this?" he snapped, gesturing to the thing, which seemed to be cowering a bit from all the shouting.

Alphys cringed. "I-I know this…it looks bad. B-but really…they're still…they're still monsters…"

Sans' sockets widened. "These are _monsters?_ What the _fuck_ have you done to them?" he shouted. Alphys hunched back.

"I…I…l-look, Sans, let me just ex-explain…"

Sans shook his head. "No…no, I'm done. I'm out. I want _nothing_ to do with you or Gaster or…or any kind of science if this is where it leads to." His eye flickered yellow as he focused on teleporting out…but nothing happened. His chest tightened, and he tried again. And again. What was wrong? Was he too far underground? Why couldn't he leave?!

He grimaced, then pushed past Alphys and the thing. One way or another, he had to get out of here. He bolted toward the room with the beds, only to clatter into Gaster. The taller skeleton caught him, staring at him in shock.

"Why on earth are you down here?"

Sans shoved him away and glared up at him. "Does Asgore know about this?" he snapped again, gesturing to the thing, whose massive tail wagged as it saw Gaster. "Because I swear to God, I will go up and tell him right now what's going on down here. You have to be some…some kind of _freak_ to do this to monsters!"

Gaster sighed, holding his head with one hand. "If you will shut off your eye, I will tell you what is happening." He narrowed his sockets at Alphys. "I expected better of you, Alphys."

She cringed again. "I…I was just…"

Gaster shook his head with a frustrated sigh. He summoned a bone, making Sans tense, then tossed it to the thing, which absorbed it into its void, tail wagging even more.

"Alphys, take the amalgamate back to its area."

Alphys nodded meekly. "C-c'mon, let's get you back with the others," she said, then guided the amalgamate out with a few whistles and a "C'mere! There's a good Endogeny!"

Sans glared up at Gaster. "You have _one minute_ to explain what you've done with these monsters."

Gaster shook his head. "Let me find where to begin…"

"How about you begin with the fact that you _experimented_ on _innocent mon—_ "

"They were already dead, Sans!" Gaster snapped. "It was an assignment from Asgore!"

Sans blinked, eye fading. "Wh-what?"

Gaster sighed. "Alphys and I were tasked with trying to find a way to inject monsters with Determination. It…well, Determination…it is…"

"It's a trait found in humans. Keep talking."

Gaster stared at him for a moment, then shook his skull. "We took recently deceased monsters and injected them with Determination, at first to preserve their bodies, then to attempt reviving them. And it was successful. They woke up and began walking around. This was…far more than we had anticipated. Alphys and I began to theorize about how we could use Determination to better monsterkind." He sighed. "But then…it turned out to be too much for their bodies to handle. They began to melt, and formed into…well, what you have just seen." He rubbed his skull. "We are still trying to remedy it, but…if there has been any progress, it is very slow. Asgore does not know the extent of the difficulty we are having, and I implore you not to tell him."

Sans' sockets narrowed. "Give me one good reason."

"His peace of mind," Gaster said firmly, meeting Sans' sockets. "You are not the only one tasked with protecting him, and I have been doing it far longer than you." He looked down, clasping his hands behind his back. "Between you and me, he does not want to hurt any more humans. It is not in his nature to want revenge, even after losing his freedom and his son. So we were tasked with finding a way to give him the Determination he needs to break the barrier." He sighed. "He has been disappointed enough. We all have. A failure like this will kill any hope the Underground has." He took a step toward Sans. "Alphys and I did not create the amalgamates out of any kind of wickedness or selfish desire. We wanted them to _live._ Surely you can understand that."

Sans swallowed and looked away, staying silent for several minutes.

"Fine." He looked up at Gaster again, expression hard. "But _swear_ you won't do this to any other monsters."

Gaster smiled wryly. "I already have."

A silence stretched between the two. It was uncomfortable, but not enough for Sans to try to run. Honestly, he wasn't sure what to do with himself after finding out what had been happening under his nose, so to speak. Finally, Gaster was the one who broke the silence.

"I cannot help but wonder why you are down here. I had done my best to keep everyone out of the lower lab since our…er, situation occurred."

Sans rubbed his neck. "Uh, well, Alphys told me to. She wants to do, uh, some kind of test on me? To see how I'm doing after the second reset."

Gaster gave a short, hoarse laugh. "Ah. I see I am not good at hiding my concern." He hesitantly set a fluttering hand on Sans' shoulder; Sans allowed it, and Gaster guided him forward. "Come. Let us find her and we will get this scan over as quickly as possible. I am certain you do not want to spend too long down here."

Sans nodded. After a few moments, he glanced up at the other skeleton. "Uh, hey, Gaster?"

"Yes?"

"The, uh, the scan…will it hurt?"

Gaster gave him a small smile. "Certainly not."

* * *

The scan went without a hitch, and Sans (quite happily, it seemed) left the lab to get some well-deserved rest. As for Gaster and Alphys, well…it was an even longer night than usual. Endogeny had made a right mess of the lab in its excitement, and the clean-up took _hours._

At last, Gaster was able to look at Sans' test results. They were worrying, to say the least: his HP was half of what a monster of his power should have, and his defenses were terribly low as well. Something clearly had to be done about that, but Gaster couldn't imagine what. His browbone furrowed as he looked over the data, searching for any other anomalies. His sockets widened as he caught something.

"Alphys! Quickly, come here!"

The dinosaur ran over as quickly as possible, goggles still on and a beaker in her hand.

"What? What is it?"

Gaster pointed at the screen. Alphys narrowed her eyes, then gasped as the beaker fell from her hand.

"My god…" she whispered.

Gaster smiled, still focused on the screen.

"It would appear that one of my hypotheses has been validated."

On the screen, right over Sans' soul, was a little red blip of Determination.


	13. Experiment

They were making steady progress with the time machine. Alphys had managed to get a small prototype up and running, and one of Gaster's crab apples had the proud honor of being the first to travel in it. Well…at least the first to disappear in it. Given how there weren't any changes in the time shift gauge, it really just…disintegrated. The three of them promptly got back to work.

Sans had a feeling most of the failure was his fault, but it was just _so hard_ to focus with the looks Gaster and Alphys kept giving him. Given how they still hadn't told him the results from the scan…well, it was just a _teeny_ bit stressful.

Finally, a few days after the test run, he set his pen down loudly enough to get the others' attention. He looked between the two, meeting each of their gazes seriously.

"All right, be honest with me. Am I about to dissolve?"

The two scientists stared at him, and Alphys broke into a sweat.

"W-what do you mean?"

"You know exactly what I mean. You guys have been walking on eggshells around me, and neither of you have brought up the scan since it happened. So what's wrong with me?'

Gaster and Alphys looked at each other for a moment, and the skeleton sighed.

"No, you are right. We should be upfront with the results." He set his pen down and steepled his fingers as he looked at Sans. "You are not in…. _immediate_ danger of dissolving, but…your HP has been halved, and your defenses are even lower."

Sans' brow furrowed. So…yeah, that wasn't great news, but he really wasn't surprised. "So what else aren't you telling me?"

A long silence passed. Finally, Alphys clearly couldn't handle the tension anymore.

"We found Determination!"

Sans' sockets widened, and he let out a nervous laugh.

"That's, uh, that's a real laugh, guys. Tickled my funny bone."

Gaster shook his head. "It is not a joke, Sans," he said quietly.

Sans stared at them. "But…but that's impossible. Determination is only found in humans."

"Not, erm, not necessarily," Alphys said, wringing her hands. "We've…we conducted some tests, um, before what happened with the Amalgamates. It was a limited pool of study, but…we did find one monster with naturally-occurring Determination."

Gaster nodded, then smiled wryly. "The captain of the guard. Since you have met her, I am sure that does not come as much of a surprise." He shrugged. "Certainly, it is not nearly so much as a human has. As we have learned, monster souls cannot handle that much. Of course, now that we know, it does make sense with you."

"Does it?" Sans asked, voice tight. "Because I'm _really_ lost here." What did having Determination mean? Would he end up like the Amalgamates, all… _melted_? Was he in danger of falling apart _any minute_?

Gaster looked up, and he quickly walked over to set his hands on Sans' shoulders. "You are fine, Sans," he assured quietly. "This Determination is not new. Nothing changes aside from what has happened with the resets. In fact, I am more than certain that it is the reason you were able to survive two of them. It gives more, er, substance to your being."

Sans grimaced. "But not enough for another reset."

"Probably not, no." He let go of Sans' shoulders to tap his jaw thoughtfully. "But…"

Sans' expression didn't lighten; he didn't like the sound of that "but". Alphys frowned as well.

"We ca-can't inject any more," she said as firmly as she could manage. "Even…even without the resets, his mass would be less than Undyne's, a-and…"

"No, no, that is not what I am thinking," Gaster assured, waving a hand. He looked down at his notes and blueprints. "Well. After such excitement, I do not think we will be able to focus. Shall we call it a day?"

Sans and Alphys glanced at each other, but didn't argue. As Alphys headed up the stairs and Sans prepared to teleport out, he felt a finger tap his shoulder. He glanced back, and Gaster half-smiled at him as he signed, "Perhaps you would like to join me for tea?"

Sans looked up at the other skeleton for a long moment. This seemed…oddly convenient. But…well, it had been a long time since the two of them had spent time together, and after the shock of hearing his results…tea sounded kind of nice. He gave the other skeleton a quick nod, and Gaster smiled as he led the way upstairs and back into the warm house. Soon enough, they were at the kitchen table, a steaming mug in front of each of them. Gaster smiled after taking a sip.

"It is almost like when we first began our research," he said, breaking the silence. His smile grew slightly bitter. "How long ago that seems now."

Sans couldn't think of anything to add to that, so he merely sipped at his tea. Another silence stretched between them. Gaster sighed.

"I know…we have not had the best time…"

"Time _s._ "

"I am sorry?"

"The best time _s_. Because of the resets."

Gaster shook his head and carried on. "Things have been tense since your second reset, and not without reason." He gave another bitter smile. "You are unnervingly good at discovering my faults, but I suppose that is to be expected wi—"

"Please don't bring up my job."

Gaster looked at the other skeleton curiously for a moment, then nodded. "Fair enough." He took another sip of tea. "But…despite all that has happened, I _do_ want nothing but the best for you, and…though I have continued to fail spectacularly in several of my attempts, I would…like to keep you safe."

Sans let out a short laugh. "I'm not a baby bones, Gaster. I've been taking care of myself for a while." He shrugged. "I mean, I appreciate the sentiment and all, but you really don't need to worry about me."

"Perhaps not two resets ago, but now I do." He sighed, tapping his mug anxiously. "If a human were to come through the Underground and make it to New Home, would you be able to fight them? Their LOVE would be very high by that point. You are clever, yes, but you are used to using your strength." He leaned forward. "Tell me, the last time you sparred with your brother, how did you manage?"

Sans swallowed, focusing down at his tea. "Uh…well…not _great_ , I guess…" Papyrus had actually beat him soundly enough to be worried. Sans had brushed it off as merely being tired; he wasn't sure if Pap had actually bought it. He shrugged. "But what can I do? Even if I adjust my strategy, it's still gonna take energy. So I'll just have to…ya know, give it my all and hope for the best."

"That is _suicide_ , Sans."

"But isn't that what I'm supposed to do? Lay down my life for the king and all that? And let's be honest, Gaster, it's not like there's anyone who can fill my slippers."

Gaster covered his sockets with a mangled hand, grimacing but not responding. Sans watched him, sipping his tea in silence until the scientist dragged his fingers down his face.

"There…may be a way I can help you," he finally said. "But I cannot guarantee its success. If it works, it will give you the upper hand in a battle. But if it doesn't…"

Sans watched the scientist intently. "If it doesn't?"

Gaster shrugged. "I do not know. I have not been able to test it. It could be as simple as wasting time or as dire as dissolving, and I…I cannot feel comfortable doing such a risky experiment on you. I would test it on myself—that was my original plan—but…" He swallowed. "But it requires Determination."

Sans' browbone furrowed. "Tell me about it, then."

Gaster let out a quick huff, then held up his hands to sign as he spoke, filling in the words he couldn't translate. "It was when Alphys and I first began our tests with Determination. Reckless fool that I am—" He paused to gesture to the cracks in his skull. "—I had decided to inject myself with Determination should the experiment be successful. I developed a…battle enhancement, let us say, that would use Determination to create a powerful attack no monster has ever had."

Sans tilted his head curiously. "But you don't fight."

Gaster gave him a grim smile. "Not lately, but I have been known to." He shook his head. "But with Asgore's first plan, if he were to break through the barrier with Determination and declare war on the humans, he would need a powerful army of monsters behind him. And…" He clenched his hand into a fist, so tight that Sans could see the tips of his fingers through the hole in his palm. "And I do not forgive as easily as he does. If I had the ability, I would not hesitate to eradicate humanity myself for what they did to our kind." He took a sharp breath, and, very slowly, his hand relaxed. "So…perhaps…it is in the best interest of all that this plan did not work. Since our experiment with Determination failed, I still have it ready for injection, but untested."

Gaster blinked a few times, then looked up at Sans as he continued, "So…I could offer it to you. If…if I have done it correctly, you should be able to use your Determination to activate it, and it will not drain you like your normal attacks. And, as we are both skeletons, it should work with your natural powers just as it would have worked with mine." His face, which had grown somewhat excited as he told Sans of his experiment's details, fell as he looked at Sans, and he abruptly shook his head. "No, no. The risk of testing something unknown on someone who is already weakened…I cannot. Forget I even mentioned it."

Sans' brow furrowed as he thought. "But…you want to test it."

"Of _course_ I want to test it! And if I knew it worked, I would give it to you without hesitation!" He let out a quick huff. "You may not like your title, but it is very apt. I have always put my work before others' safety. First the Amalgamates, then the researchers…" He covered his face. "For _once_ , I would like to put life before progress."

"These things aren't your fault."

Gaster looked up, sockets wide. Sans swallowed and traced the top of his mug.

"Look, I make a lot of split-second decisions. I've been trained to, ya know? So I, uh, judged too quickly with…a lot of this." He sat up a bit. "I mean, the Amalgamates…you were trying to save them. And it's not like you're gonna kill them just because they're scary. And the researchers…you warned us. But all of us got carried away, me included. I was just lucky. And…when I freaked out at you after the Terrin thing…" Sans rubbed his forehead. "I was still really shaken up over Papyrus' death in the last timeline. I _still am_ ; I get nervous when I can't keep an eye on him." He let out a quick breath as he looked up at Gaster. "But…in the end, it's the intentions that matter, right? Your 'failures' were when you were trying to help people, and…I think that counts for something."

Gaster stared at him for a long moment, lost for words. Finally, he half-smiled, letting out a small, hoarse laugh.

"And what of selfish intentions?" he asked softly. Sans shrugged.

"I don't know. I can't read thoughts. So it's really up to you to decide if what you did was selfish or not." He chuckled a bit. "Honestly, I'm an awful Judge. I just push all the work to the person being judged."

"I would disagree. You still seem quite adept in your role."

"Heh…" Sans looked down at his empty mug. "Well…I'm pretty sure I think more like a scientist than a judge." He thought for a moment, then looked up at Gaster. "I want to try your experiment."

"Sans…"

"No, Gaster, I want to. I'm a wreck right now; the only way I can go is up, right? And if the worst happens…I mean, Papyrus _is_ an adult, technically, and there'll still be plenty for him to live on."

Gaster looked at the other skeleton grimly. "So you really are serious about this?"

"C'mon, Gaster, you know me. I'm _always_ serious."

Gaster eked out a small smile, then let out a soft sigh. "All right. Then we will do it."

* * *

Given the nature of the experiment, they weren't able to hop down to the lower lab and do it just then and there. And, given that Alphys had built the machine they would use, she had to be told of the plan, and, while she told Sans that it was his decision and she respected that, she and Gaster spent the next few hours in a corner of the grey room, whispering angrily to each other. So…it wasn't hard to imagine that she wasn't keen on the idea.

Sans sighed as Gaster stalked away from their angry corner, signing some very aggravated things as he walked up to the door. He probably needed to cool off after the whisper-fight. Obviously it was time for Sans to jump in. He set down his pen, then walked over to the corner. Alphys, looking actively _angry_ , was hammering at some metal with far more force than necessary. He looked at her for a moment, then gave a little cough to get her attention.

"Uh, hey, Alphys." She didn't look up, and Sans shifted back and forth. "Look, I know…you really don't want to do anything with Determination. I get it. But…"

"There isn't a 'but,' Sans!" Alphys interrupted. Sans blinked. _Wow._ He didn't know she _could_ interrupt. "We learned our lesson with the Amalgamates! Do you know how many letters we get asking about family members _every day_? You think I want to add _another_ casualty to the list?"

Sans grimaced. "Alph, I know. _I know._ But…look, with the way my job is, I really can't…"

"It doesn't matter! I can't _ethically_ do this! Whatever your job is, you don't need—"

"I'm the _Judge_ , Alphys!"

That shut Alphys up. The anger melted from her face as she stared at Sans, a mixed look of surprise and horror replacing it.

"Oh, _god,_ so you _…_ "

"No! No, we _do not_ have time for you to freak out over that," Sans said firmly. "Look, I'm the last line of defense for Asgore. If a human manages to get through everything else down here, I'm _useless_ right now. And the possibility of it _working_ is well worth the risk of me dissolving; trust me, I spent all night thinking it over. I can pull up ratios if you want!" He huffed out a breath, setting his bony shoulders. "But it's the only way I'll be able to do my job and keep Asgore safe."

Alphys wrung her hands anxiously. "But it's not _tested!_ "

"I know. I'll be the test subject. It's fine." Sans took a step toward her. "We really don't have any time to lose, Alphys. Another human could come any day now, and I _need_ to be able to fight them."

Alphys' face screwed up tightly. " _Fine!_ Okay! We'll do it!"

Sans' face brightened, his grin genuine now. "It's worth it, Alphys, I promise. It's gonna be worth it," he assured. Alphys didn't look nearly as excited as he felt, and she turned back to her sheet of metal.

"Tomorrow. I need time to get the machine set up; it's been a long time since we used it," she said, hammering again.

"Tomorrow's great."

As Sans headed toward the door to tell Gaster the news, he paused as he heard Alphys whisper, "Uh, Sans?"

"Yeah?"

Alphys took the hammer in both her claws, tugging at it nervously. "Erm…the whole Judge thing…I'm not…I mean, god, this sounds stupid…but the whole thing with the Amalgamates…"

Sans looked at her for a moment, then gave her a wink.

"I'm off-duty whenever I'm here, Alph, and you know how much I hate overtime. The only thing I've judged you for is your taste in shows."

Alphys gave a huge sigh in relief, then looked up at Sans again, offended, and shouted after him as he exited the grey room.

"Mew Mew Kissy Cutie is a _national treasure!_ "

* * *

Sans was having second thoughts. And, while he'd had second thoughts several times throughout his life, particularly the past few months, now he was _really having second thoughts._ He had been fine through the night, and even up to this morning. Hell, he'd brought a few bones along just in case Endogeny was around again. But now, as he sat on the metal operating table, staring at the _massive_ machine looming just above him…yeah, it was time for second thoughts.

He looked over at Gaster and Alphys, both looking at a screen just over the control panel. Gaster held a little glass tube, filled with what appeared to be bright blue light.

"Yes, you see, we will insert this where we put the Determination last time, and the rest of the injection should be exactly the same," Gaster was explaining.

"That's still an awful lot of power; I think we could tone it down," Alphys argued, tapping at the controls. "The Determination _didn't_ want to go into the monsters; you said this would bond to the Determination in him."

"I said I _theorized_ it would. I would rather be safe."

"I know, but it's one thing to use massive force to get Determination into a dead monster and a whole other to use the same massive force on a living one…"

"Uh, guys? If it's, uh, if it's not too much trouble, could you maybe…not discuss this so loudly?" Sans piped up, voice tight. Gaster looked up, and he nodded.

"Yes…I suppose this is a little unnerving. Could you lie down, Sans? We are just about ready to start." Gaster inserted the tube into an opening in the machine, still whispering to Alphys.

Sans laid down and took several deep breaths, shutting his eyes. He could do this. It was all or nothing. He would either feel the same, feel better, or dissolve. And while the last one _certainly_ wasn't ideal, it was the only way things could get worse. Even so, his bones rattled against the metal table, and he let out a sharp gasp as he felt something brush against his skull, eyes flying open.

"It is just me," Gaster assured quietly as Alphys made her final adjustments. "If you would like, I will stay with you during the injection."

Sans swallowed and nodded. He looked at the machine as it moved to position itself, then back up at Gaster. He brought up his hands to sign, "Will it hurt?"

Gaster grimaced, and he hesitated before signing back, "Yes."

Sans took several breaths, then looked up at the scientist again and quickly signed, "Will I be okay?"

"Yes." There was no hesitation with this answer.

Sans let out a shaky breath, then let his arms fall to his side, only for metal clamps to secure around his wrists, arms, legs, and ankles. He let out a cry of alarm, automatically struggling against them.

"Do not panic, Sans! You are not in danger," Gaster quickly assured, hands resting on Sans' skull. "These are merely to keep you from being harmed."

Sans stared up at him, sockets wide with fear. Gaster's brow creased.

"Please, Sans, trust me. You will be _fine_ ," he whispered.

He felt a twist of dread build in his chest, but…what else could he do? He let out one last shuddering breath, then shut his eyes. He felt Gaster's thumbs lightly press against his temples, one last, silent assurance.

"Alphys. Turn the machine on."

Sans heard the click of a button and the whir of a machine, then all at once a blinding hot pain seared through every bone in his body. He could hear the roar of mechanics and a scream that sounded like it belonged to him, but they sounded so far away, muffled as his brain tried to process the way it felt like each bone was on fire. He thrashed against the restraints, his head trying to pull away from Gaster's hold, but both kept him in place. He couldn't breathe, couldn't see…at any moment he was just going to break apart…

" _Turn it off! Turn the machine off!"_

Somewhere, he heard Gaster yell above the far-away noise. The room went silent, and the pain stopped. Sans went limp on the table, taking gasping, ragged breaths as he trembled. Fingers ghosted along his browbone, just gently enough to not hurt.

"You are safe. It is over."

Grey static crept into his mind, getting louder and louder as he felt himself start to slip into unconsciousness, away from the pain and fear. One whisper reached him as he fell away.

"Please, _please_ , do not let this be like the others."


	14. An Announcement from EO

Hey, guys!

I know, I know, authors notes as chapters are THE MOST ANNOYING thing, but this is important and I don't want to leave you guys in fic-reader-limbo, because I've been there and it SUCKS.

Anyway, I'm juuust starting the final stretch in my MA degree, which means I have a shitton of stuff to research and write before the end of April. So, unfortunately, that means Reset's gonna have to go on the back burner for now. I may be able to squeeze in another chapter over Easter break, but I'm also travelling with family during that time, so it's not a guarantee.

THAT SAID, I absolutely have every intention of finishing this story. It's all mapped out and I have a clear ending in sight. More than likely I'll be doing another big five-chapter-dump during May-June when I have a lot fewer projects to work on.

Seriously, though, thank you guys SO MUCH for all the faves and comments. It really does mean a lot to me, and I'm looking forward to when I can come back to this.

~E.O.


	15. Recovery

Before he was even fully conscious, Sans knew that he _hurt. A_ _ **lot.**_ Just the slight movement he made as he woke was enough to send all of his bones screaming.

With a grimace, he exhaled and slowly opened his eyes, the room coming into focus. And it…wasn't his. He half-bolted up, stopped by a wave of pain. Where was he? How long had he been asleep?

"Pap…" he called hoarsely, pushing past the aches to try and get out of the bed, but his body just wasn't having it. He toppled onto the floor in a heap of sheets and bones, crying out in pain and unable to even push himself up.

Almost immediately after falling down, he heard frenzied footsteps, and the door banged open.

"My god, _Sans!_ "

All at once, another wave of pain hit Sans as he felt himself be scooped up and set back on the bed. He squinted his sockets open, taking deep breaths to counteract the waves of pain still hitting him.

"G-Ga—"

"Hush. You are fine." Gaster very gently adjusted the sheets and blankets over him. "Though you should not be awake yet, much less trying to get up. That is my mistake."

Sans shut his eyes again as his breathing evened. Finally, once he was able to, he peeked his sockets open and asked, "Where'm I?"

Gaster's hands fluttered—not a word, just him trying to think. "Er, my house. My apologies, but I did not know where you live." He looked over Sans for a moment. "But I will explain later. I will be back. Er, please do not try to move again." He quickly turned and exited the room. Sans let out another breath and grimaced as he settled back against the pillows. Gaster definitely didn't have to worry about him running away.

Eventually, the scientist returned, a steaming mug in his hand. He very carefully sat on the edge of the bed.

"Just another moment," he said, swirling the cup. Sans watched him with half-shut eyes.

"How long've I been 'sleep?"

"About twelve hours. Not nearly long enough for you to recuperate."

Sans' sockets went wide and he half-sat up. " _Twelve hours_?! But _Papyrus_ …"

"Sans, do not move so much," Gaster scolded gently. He gave the mug one last swirl. "I found Papyrus while you were asleep and let him know you were, er…" His free hand waved, but Sans couldn't even begin to try translating the vague motion. "…well, I said you were…recuperating, I think, is the word, here after an incident at the lab. He is fine, if worried." He smiled. "You are fortunate to have such a caring brother. Now, I will need you to drink this."

"Whuh is it?"

"Something to help you sleep a little longer." Gaster tipped the mug against Sans' teeth, and a warm, thick liquid poured into his mouth. Despite the pain and grogginess, Sans still made a face at the awful medicine-taste, but the moment he finished, he felt his eyelids drooping. He relaxed against the pillows, vaguely aware of a fluttering hand just barely brushing against his browbone.

"I will explain more later," Gaster murmured just as Sans dropped back into unconsciousness.

* * *

The next time he woke up, he only had a moment of panic before remembering where he was. He sighed and settled back into the bed; the pain wasn't quite so bad this time around, but he still wasn't about to get up and start dancing about. Instead, he looked around. Like the rest of Gaster's house, this room seemed pretty bare—a dusty dresser and the bed were the only furniture, and there weren't even curtains on the one window. Then again, Sans really wasn't one to judge (he couldn't help his little laugh as he thought that); half the time he couldn't be bothered to put the sheets on his own bed.

He looked up as he heard a brisk knock on the door. "Come in."

The door opened, and once again Gaster stepped in, this time with a tray in hand. He smiled a bit as he looked over Sans.

"You are looking much better this time around; I am afraid my medical experience is…er, rusted?" He set the tray down on the dresser, opening a jar and scooping something into a steaming mug.

"Rusty. What's that?"

"Honey…a bit of a rarity down here, but it has several health benefits attached to it." He smiled at Sans. "And it goes splendidly with golden flower tea. How are you feeling, Sans?"

" _Sans_ ational," he grunted, sinking back into the pillows.

"Evidently not in much pain, then. I will let your brother know he can come up."

Sans perked up. "Papyrus is here?"

Gaster chuckled slightly as he stirred the honey into mug. "He arrived soon after you went back to sleep, and he insisted on waiting outside until you could see him." At Sans' look of alarm, he added, "I did not leave him out there; he is downstairs."

Sans relaxed and chuckled. "That sounds like him. He did the same thing to Undyne, just waited outside her house all night to convince her to let him into the Royal Guard."

Gaster arched a browridge as he handed Sans the mug. "Oh? Perhaps Determination is hereditary…"

"Don't you even…"

Gaster chuckled. "I would never, do not worry. All my tests are done on volunteers…provided they are living, obviously." He sat on the edge of the bed. "Though, speaking of, we did have one success with the experiment, at least."

"Yeah?"

"You survived."

"Heh, guess that's pretty good." Sans' browbone furrowed as he sipped at the tea. "So, uh, how _will_ we know whether it worked or not?"

Gaster shrugged. "We will have to test it. But not until you are recovered; as of right now, I would not want you to risk the exertion."

"God, no." Sans couldn't even _imagine_ anything close to fighting right now. Really, he wanted to sleep for another ten days or so, but Papyrus was waiting. He looked down at the mug—probably best to finish this before seeing his brother. Drinks usually ended up on walls after Papyrus' greetings. "Hey, so…you're a medical doctor, too? I never figured you for one."

One of Gaster's cheekbones pulled up in a strange grimace. "Well, technically I am not. Monsters tend to recover from sickness with ease—there was a scare when Asgore was accidentally poisoned, but—"

" _What_?!"

"Be careful, Sans!" Gaster held up a hand to stop the cup from tipping over. "You have never heard that story? His children—certainly you know their story—made him a buttercup pie. Buttercups are quite toxic when eaten. The queen had done fairly well with taking care of him—she was quite the healer—and I had suggested some treatments if his condition worsened, but it did not." Gaster's face shifted, as if he had tasted something bitter. "Humans, however, do not fare as well with sickness. The queen's methods were not as effective with their child, and I was called in."

"Really? I'm…uh, kind of surprised you went with it."

Gaster's face was grim as he looked down at his hands. "You do not have a choice when the King begs for help."

"So you _didn't_ want to."

"You know my feelings toward humans, Sans. And this one..." Gaster sucked in a breath, then quickly got to his feet. "Well. It is not important."

Sans groaned. "You _can't_ say something like that and leave me hanging."

Gaster looked back down at Sans for a moment. "Perhaps later." He gave him a small smile. "But for now, I think your brother is quite anxious to see you, and I do not want to keep him waiting." He exited the room before Sans could protest anymore.

Sans huffed at the door as it closed, then drank down the last of his tea before (very, very cautiously) teleporting the mug over to the dresser. It had barely clinked down before the door practically exploded open.

" _Sans!_ "

Before he knew what was happening, Papyrus had more or less launched himself onto his brother, hugging him tightly. Sans winced, then wheezed out a chuckle as he pat Papyrus' bony back.

"Hey, buddo. Ya miss me that much?"

"I heard you'd been hurt!" Papyrus let go and sat back on his knees. "What happened?" His sockets narrowed. "Was it a… _human_?"

Sans held up his hands. "Hey, hey, calm down, Pap. I'm _fine._ I just got a little excited over winter starting."

"Sans, it's spring."

"Are you sure? Because I had a bad _fall._ "

"THAT ISN'T FUNNY, SANS!"

"No? Guess I'm not a _season_ -ed comedian just yet."

"SANS, YOU COULD HAVE DIED!"

Sans winked. "Me? _Die_? No way, Pap. I've still got _au-tumn_ of jokes left to tell you."

Papyrus huffed, crossing his arms. "Well, despite your _terrible_ sense of humor, I, the GREAT Papyrus, will do my best to nurse you back to full health!" He smacked his palm with a fist, bones clacking together. "I'll give you round the clock care! I'll take you out on our patrols, even! In a-a wagon!"

"Pap, I don't think…"

"Er…apologies for intruding…" Both brothers looked up as Gaster poked his head in. "I could not help but overhear." He tapped his fingertips together. "But, er…I think it may be better if Sans remains here. He is, ah…not in patrolling condition." He gave a hesitant smile. "But…perhaps…you might stay here as well, for the time being? I am rarely here, and it does seem convenient for your station. We, er, would need to put in a bed next-door, but…" He shrugged. "It would be easier than travelling from the Core, I think."

Papyrus brightened. "So close to work?"

Gaster smiled. "You will be able to come back and check on him throughout your patrol." He turned as a whistling came from downstairs. "Ah, that is the sedative. Please, think about the offer."

Papyrus grinned as he turned back to Sans. "This is a great solution! Much better than mine!"

"Yeah, uh, I like it a bit better than being pulled in a wagon."

"And we'll be _at work!_ I'll be able to patrol by myself no problem whi—"

"No," Sans interrupted sharply. "You can't. Not by yourself."

Papyrus sat up straight, looking at Sans with wide, confused sockets. "What? Yes, I can."

 _Take it easy on me; I'm just a flower!_

The voice grated in Sans' head. What if it found him in Snowdin? " _No_ , Papyrus, you _can't._ "

"Why not? I'm at least as strong as actual Royal Guards and-"

"Because!" Sans snapped. He looked away, not wanting to meet his brother's sockets as the memory of holding a plastic bottle of dust flashed in his mind. "Because…because…."

He couldn't finish that sentence, and they slipped into silence.

Until, in a voice far meeker and softer than Sans had ever heard from him, Papyrus asked, "Do you…think I can't do it?"

" _What?"_ Those words came like a slap in the face. "No, no, Pap, I-I just—"

"Because…because I really can! Really! I've been training _so hard_ with Undyne and my special attack is _really, really_ cool and! A-and I think if I…"

Sans watched his brother talk, not hearing the words.

Wow.

He was well on his way to fucking up with this argument.

Not even a whole day earlier, he'd been assuring himself that Papyrus was old enough to take care for himself. And he _was._ Sure, he was kind and naïve and way too trusting…but he wasn't _weak._ And he wouldn't be able to get any stronger if Sans kept playing big brother. He couldn't just… _stop_ him out of fear of a little danger. Or even a _lot_ of danger. His baby brother wasn't a kid in striped shirts anymore.

Maybe it was time he started respecting that.

"Sans? Sans, are you listening?"

Sans blinked, abruptly pulled out of his thoughts. "Uh, yeah. Yeah, sorry."

Papyrus huffed. "Were you sleeping with your eyes open? I know you're not well, brother, but that's impressive even for _your_ laziness!"

Sans' cheekbones lifted. It was a little forced, but he had to sell this to himself. He winked.

"Nah, bro, I am absolutely, completely awake." He rested his jaw on his hand. "And I know you're able to fight just fine. I'm just worried you'll ruin my sentry station with all your _tidiness_ if I don't keep my eye on you _._ "

Papyrus crossed his arms with a huff. Despite his act of annoyance, Sans could see the relief on his brother's face. "Because of the situation, I swear to keep your post in its typical horrifying state."

"Thanks, Pap. I know you'll keep me…. _posted._ "

" _SANS, OH MY GOD._ "

* * *

The next day, Sans couldn't help but feel anxious as he heard Papyrus leave the house for his patrol. He needed to keep his mind off of the possibilities and the need to keep an eye on his brother; he didn't want to risk teleporting into the middle of Snowdin in his condition. So, when Gaster came in to bring him a mug of tea and a mild sedative for the pain, he was immediately ready to kickstart a conversation.

"All right, Gaster, three questions."

Gaster looked at the other skeleton in surprise, then smiled as he set the tray down. "Very well. I will answer what I can."

Oh. That was easier than he thought it'd be. "Okay, first off, what does W.D. stand for?"

Gaster blinked, then let out a loud laugh. "I am sorry?"

"Your name," Sans clarified. "I've been trying to figure it out since we met."

Gaster shook his head, still smiling. "It is awful. I prefer going by my family name."

"That doesn't answer my question at all."

"That was the point."

Sans groaned, head falling back against the pillow. "C'mon, it can't be _that_ bad. 'Sans' isn't exactly great."

"Only because you do not know your history. There were quite a few Sanses in the village, from what I remember," Gaster said as he poured hot water into the two mugs. He glanced up at Sans, then sighed as he bobbed the teabag into one mug. "Wing Ding."

"What?"

"My given name is Wing Ding."

Sans' cheekbones lifted a bit. "Oh my god. That's great."

"I do not appreciate your patronizing, Sans," Gaster scolded lightly. "It is terrible when spoken. It is meant to be signed."

"So how do you sign it?"

Gaster glanced up again, then smiled a bit before his hands gracefully signed his name, gliding from one letter to another. "It is an old name, but still elegant in its proper language." He pulled out the tea bag and spooned out some honey into both mugs—it made the sedative go down easier. "Tea first?"

"Yeah. And, uh, second question." Sans took the warm mug from the other skeleton. "Why are you letting me and Papyrus live here?"

Gaster again blinked in surprise at the question, though he didn't laugh this time. "I explained yesterday. It is convenient. You are still recovering, and I do not think Papyrus wants to be apart from you any more than you want to be from him. And anyway, I have not slept here once since the, ah, issue with the amalgamates. It seems like a disservice to the king to let this house go to waste."

Sans looked down at his tea, rubbing the side of the mug as he thought. He hadn't known what to expect with that answer, really, but…it was a lot simpler than he'd guessed. "We won't stay too long."

Gaster smiled. "That is not an issue, Sans. At any rate, it is nice to see some life in here."

Sans glanced up and lifted his cheekbones again, returning the smile. "Well…it's, uh, it's really appreciated." He took a long sip of tea. "All right, third question."

"I am ready," Gaster said as he stirred the mug with the sedative.

"When were you planning on telling me you'd reset?"

Gaster dropped the spoon with a loud clank. "I am sorry?"

"Heh. So I was right." Sans took a sip of tea. "Well, it _was_ just a guess. But you noticed that my mouth stopped moving—according to my notes, the only ones who noticed the change were people who had reset. And also…" He winked. "…you've gotten better with the language. When we met, you could barely get through a sentence without needing something translated."

Gaster blinked, then smiled and shook his head as he sat on the edge of the bed. He was silent for a long moment, then laughed. "It is a shame I have grown cautious in my old age. If I had gotten to you before Asgore, given you the same training I have given Alphys, imagine the scientist you would be with your perception!" He smiled and shrugged. "I suppose it should not be much of a surprise that I did reset, despite my warnings. I am a scientist, and theories are meant to be tested."

Sans sat up eagerly. "So how far did you get?"

Gaster was silent again, and his smile faded as he looked down at his hands.

"Far enough."

Oh. Sans sat back. "You didn't get where you wanted to."

Gaster shook his head. "We all have foolish wishes. I should have known I was setting myself up for disappointment." He let out a bitter laugh. "Even a human could not go back almost a thousand years."

"A thous—!"

"I know…I know." Gaster sighed, resting his skull in his hand. "As I said, it was a foolish wish."

Sans rubbed his knee, browbone furrowed.

"Why'd you want to go back that far?" he asked quietly. "That'd just take you back to the war, wouldn't it?"

"Just after." He covered his eyes. "When…when we were forced underground, everything was in absolute chaos. Monsters panicking, several injured, families separated. The group I was with…the few skeletons that escaped from our village, I lost them as we fled, and it was many years before I could speak well enough to ask where they were. By that point, I think your parents were all that were left." He dragged his hand down his face. "But I thought…if I could go back as I am now…if I could just _speak_ …"

"You could save them?" Sans' voice was soft, and he had pulled his knees up to his chest, like a kid listening to a story.

The scientist swallowed. "It is…complicated. Monsters and skeletons have many fundamental similarities…but we are not entirely the same." He waved a hand. "It is likely different for you and Papyrus—you were raised as monsters, more or less. But to be without your own kind, your own culture for so long…" He swallowed again and was very still for a few minutes. Finally, he signed, "It is very lonely." He pulled a face. "I would not be so selfish if I succeeded."

Sans grimaced as well. "You, uh, you're really stuck on this selfish thing. I really think you're being hard on yourself."

Gaster shook his head. "You do not understand. My motivation for _everything_ is self-serving. The tests for Determination, the resets, the awful experiment I put you through…"

Sans' brow bone furrowed. "But you said…I mean, that was to stabilize me, right?"

Gaster shut his sockets. "Yes."

"So then—"

"But I suggested it because…because I could not bear being alone again."

Silence fell, and Gaster covered his sockets, his shoulders—well, really, his whole _body_ sagging. Sans fiddled with the corner of a blanket, unsure of what to do. Papyrus was the one who was better with dealing with emotions. But the Papyrus mode of aggressive kindness didn't seem like Gaster's thing. But…well, maybe he could do something.

"Hey, Gaster?"

The scientist let his hand fall to his lap, sockets turning toward him. Sans' brow furrowed, and he moved his hands slowly, so as to get the grammar right.

"You are not alone anymore," he signed, hands hesitant but clear. He shrugged. "You have me. And Papyrus, too." He winked. "He will be harder to get rid of, honestly."

Gaster stared at Sans for a long few minutes. A _long_ few minutes. Had he signed something wrong? What if he'd insulted him?

"Uh, Ga—"

Sans was cut off by the last thing he expected.

Gaster was _hugging_ him.

Well, sort of. It was the kind of hug that someone who was not a regular hugger would give. Definitely not the bone-crushing squeezes Papyrus—and Sans, on rare occasions—gave. It was delicate—not so much squeezing him as carefully enveloping him, giving him the option to pull away. His dad had hugged him the same way. Huh. Maybe it was a skeleton thing.

"You and Papyrus have me, as well."

The words were soft, but they still struck Sans to his core, reverberating through his bones and just barely making his sockets wet. He couldn't say why. Maybe because he was tired. Maybe because he was still terribly sore and drained from the experiment.

Or maybe it was because, for the first time since his parents had dissolved, it didn't feel like the whole Underground was on his shoulders.

Or…maybe…for the first time in a very, _very_ long time, he felt like he was _home._


	16. Darker Still

They didn't mention their conversation after that. Really, there just wasn't time. There was still a lot of work to do, and Sans needed to make as quick a recovery as possible to get back into it. The week following the experiment was the worst; he _tried_ to work, but between the pain relievers and the lingering exhaustion, he couldn't force his brain to create equations, and the pages that soon littered the floor mostly comprised of incomprehensible scribbles and doodles.

True to his word as always, Papyrus _was_ being an aggressively attentive nurse. The pain meds were given _right_ when the next dose was due (and not _any_ sooner!), mugs and bowls were whisked away as soon as they were emptied, encouraging notes were left on what Sans should do to maximize his recovery whenever Pap was out on patrols ("STEP ONE: TELL YOURSELF THAT YOU ARE GREAT (NOT AS GREAT AS ME, BUT THERE IS ALWAYS ROOM FOR IMPROVEMENT, BROTHER!). STEP TWO: MAKE SURE YOU EAT A GOOD MEAL (THIS WILL BE BETTER WHEN UNDYNE TEACHES ME HOW TO COOK). STEP THREE: REPEAT STEP ONE, BUT THIS TIME DOING JUMPING JACKS.") , and, on the rare times where Sans _wasn't_ asleep by the time night fell, Papyrus would break out "Peek-a-boo With Fluffy Bunny" and read to him. Sure, it was a little stifling, but Papyrus _did_ make sure Sans was well-taken care of. Plus, the role-reversal was a bit of a reassurance—with Papyrus being Sans' caretaker instead of the other way round, Sans could believe that he was safe in the outside world.

As for Gaster, he dropped by a few times during the week, but wouldn't visit long. With Papyrus taking care of the medical stuff, Sans guessed he was putting his time into the amalgamates.

Regardless, he was going completely stir-crazy by the start of week two. It was time for an experiment. The past few days, he'd practiced teleporting pencils and mugs, half to see how he was faring and half for convenience. It didn't seem to affect him, so, hopefully, he could teleport downstairs. He wouldn't be able to do much—the few times he'd walked around the room left his bones aching—but it would at least be a change of scenery.

He focused hard on visualizing the sofa, thinking of _exactly_ where to land—maybe it was overkill, but he'd rather not be found on the floor. He let out a breath, feeling the familiar surge of power—though a bit weaker than normal—and was dropped onto the couch a moment later. He grimaced at the initial impact, then relaxed with a contented sigh. Good to see that hypothesis worked; plus, teleporting seemed to take less energy than walking. Maybe he could teleport to the grey room? It wasn't as deep as the lower lab, but…

He sat up a bit as he heard voices in the kitchen.

"You almost have it. You simply need to flick your wrist a bit faster."

"Like this?"

"Yes! Yes, that is it exactly! Now try again."

It took a bit of effort and a bit of pain, but Sans was able to move his head enough to peek into the kitchen. His brow ridge rose as he saw Gaster and Papyrus; the latter was looking absolutely focused as his hands signed, with surprising clarity, "I AM DOING WELL TODAY!" (Somehow, even when using a silent method of communication, he managed to be loud.) Sans stretched his neck out a bit more, but his placement on the sofa wasn't as centered as he thought

The clatter of bones hitting the ground and a few choice words brought both of them rushing out as he pushed himself up and leaned back against the couch. Gaster opened his mouth, but Papyrus was quicker.

"Sans, what are you _doing?_ You need to be in bed!"

Sans shrugged. "I, uh, decided to do an experiment." He nodded behind him. "You can see I didn't get _sofa_ -r." With a grunt, he pulled himself up onto the couch. "See? I'm fine."

"You are NOT fine! We need to get you right back up-"

"How did you even get down here?" Gaster asked, lightly patting Papyrus' shoulder in apology as he cut him off.

Sans winked. "I took a shortcut."

Now it was Gaster's turn to worry. "You _teleported_? Sans, you are already in a fragile state and—"

Sans held up his hands. "I'm fine! Both of you, I'm fine. I'm still here, still solid, everything's good. I won't move anymore."

The other two skeletons both opened their mouths to protest, and Sans quickly changed the subject. "So, uh, looks like you're a natural with the language, Pap."

Papyrus's brow bone furrowed, and he shut his jaw as he thought over that. Suddenly his sockets widened. "Oh! The skeleton one!"

Gaster sent a somewhat annoyed look at Sans—he saw what he was doing—then let out a breath as he shook his head, trying to hide a small smile. "Well, part of that is because, unlike _someone_ , he actually practices."

"Hey, I put a _ton_ of work into the language." Sans winked. "A sk—" He was cut off as he was abruptly picked up and—as unceremoniously as possible while being careful—was slung on Papyrus' back.

"NO. TIME FOR BED."

"Papyrus, I just woke up." Sans turned to look back at Gaster, who was clearly trying not to laugh and showing no indication of helping him. "Seriously, the cops'll come soon if you don't put me back."

Papyrus stopped on the stairs, glancing back at Sans worriedly. "Really? Why?"

"Because I'm resisting _a rest._ "

"SANS, I WILL DROP YOU."

"No, you won't."

"I WILL VERY SERIOUSLY CONSIDER IT!"

Sans laughed and gave up; at least he knew he could move around a bit, even if he had to wait for Papyrus to go out. He looked over his shoulder again. "See you later, Gaster!" He awkwardly turned and signed, "I be down here," before he winked.

Gaster smiled and gave a wave of acknowledgement. He watched the brothers argue for a moment longer, then let them be as he quietly slipped out of the house and to the grey room below.

* * *

It was quite a while before Gaster returned, but not without excitement. He burst into the house, waving notes in his mangled hands. "Sans, we must call Alphys, there is—!" The scientist frowned as he looked in the empty room. This is where he had said—Gaster checked his watch. _Oh._ It was later than he thought. He shook his head and made his way up the stairs, taking them two at a time. Regardless of the time, this was quite the development, and they needed to—

He opened the door, not bothering to knock, then stopped. Sans was in bed, fast asleep; he'd expected that. What he didn't expect was the quantum physics book in the snoozing skeleton's lap, or the pages and pages of equations and notes that were scattered all over the bed and the floor—he even still had a pen in his hand.

Despite the mountains of work around him, though, Sans looked quite peaceful. And so… _small._

Gaster let out a breath, then looked down at his own notes. Well. It wasn't a _life-threatening_ development _._ He supposed they could go over it in the morning. As quietly as he could, he walked over to take the pen from Sans' hand, setting it down with his notes for Sans to look over in the morning. He stopped for a moment, hand hovering over one particular paper. It wasn't equations, just a little drawing. Sans was prone to doodling when he thought, so it wasn't surprising.

All the same, Gaster took it.

He'd never had a family portrait before.

* * *

"I'm still _really sorry_ I haven't visited!"

"Alph, you've been here for an hour. You can really stop apologizing. You didn't even need to apologize the first time."

"But _still!_ I'm the _worst friend!_ "

"No, you'd be the worst friend if you used my current condition to make me watch Mew Mew Kissy Cutie again." Sans used his pen to point at the television screen, where a cartoon about giant robots blowing stuff up was playing. "This is kinda cool."

Sans had found Gaster's notes when he'd woken up that morning—along with a smaller note assuring that they would discuss them after a DT meeting with Asgore. Not wanting to go through all this science alone, he had called Alphys over not much later; she wasted no time in coming, bringing along a bag full of videos and instant noodles as a "get well soon/sorry I'm part of the reason you're in a ton of pain right now" present. It would have been kind of fun—like a study party—except that the notes were all typed up in Gaster's strange language, making a quick skim impossible. Sans was _able_ to translate them, yes, but it still took a lot of work. He slouched down in his seat with a huff.

"How does he even type this?" he grumbled. Alphys grimaced.

"Erm, my fault. I…well, see, he was getting really frustrated that he had to translate his notes before typing them up, so I, um, I made a program? With his alphabet?"

"Okay, _that_ puts you in the running for 'worst friend'. You're making me do all this work." He scribbled down another line, then tapped his pen against his teeth. "All right, I've got the first page." He held up the paper. Around several scratched out misspellings, the following was written:

 _entry_ _number_ _seventeen_

 _dark darker yet darker_

 _the darkness keeps growing_

 _the_ _shadows cutting_ _deeper_

 _photo_ _n readings negative_

 _this_ _next experiment seems_

 _very_

 _very_

 _interesting_

 _…_

 _what do you_ _two think?_

The two of them looked over the page, silent for a couple minutes as they processed it. Sans finally shook his head.

"He's so dramatic."

Alphys snorted. "Sans! This is serious!"

Sans shrugged with a wink. "I'm making an educated observation." He looked at the paper again. "D'you know what he means by experiment?"

Alphys shrugged. "We haven't planned anything with the machine since you've been recovering."

Sans nodded, reading over the page again before he huffed. "He really didn't give us much to work with. Just…everything's dark."

Alphys pushed her glasses up a bit as she looked at the page. "Well, he's probably talking about the time gauge. You know, downstairs."

"Does that measure _photons_ , though? It's, uh, that's light, right?" He grabbed the quantum physics book on the side-table, awkwardly flipping through it with one hand.

"Oh, god, right, you're still learning this stuff." Alphys puffed out her cheeks. "It's, um, well, it's…basically light and all other kinds of electromagnetic radiation? Because, um…god, I'm so bad at explaining this…well, okay, so it's hard to measure _time,_ because it's, y'know, relative. Especially down here, since we kind of have to make up how long a day is. So the prototype, it, erm, it measures fluctuations of EM radiation…there's allowances for magic and stuff, but it should still stay pretty stable." She frowned, taking the paper from Sans to look at it again. "But if there was a reset—based on what you wrote—then there should have been a dip in the readings. It shouldn't have gone completely into the _negatives_. That'd be the absence of, well, anything."

Sans blinked. "So…did we just stop existing for a bit?" He tapped his pen to his jaw. "I would have felt a reset—after you've done one, you know what it feels like—but things have been steady."

Alphys shook her head, looking at the paper hard. "I don't know, I really don't. I think we're just gonna have to go through the rest of his notes."

Sans groaned, lightly hitting his head against the couch cushion, then let out a sigh before he grabbed the notes and got back to translating.

* * *

They got through another three and a half pages of the notes before Sans, hand stiff and vision slightly unfocused from staring at the symbols for so long, suggested they call it quits until Gaster returned; that way, they could just _ask_ about the notes. He had to give it to Alphys—anime was a pretty easy thing to stare at when your brain needed to just stop. Humans were terrible, no doubt, but they had come up with some pretty good ways of killing time; definitely beat out watching a mechanical rectangle dump rose petals on himself for four hours.

They both perked up as the door opened, and Gaster wasn't even in sight before he asked, "You have read through the notes, Sans?" As he entered the room, he was practically buzzing with excitement. "Alphys! I did not expect you here already, but I am glad! We have so much to discuss!"

"Like what this next experiment is?" Sans asked, holding up the first page of notes. Gaster grinned, pulling a crab apple out of his coat pocket.

"Considering you are mobile, I think it is time we tried the machine again."

Alphys fiddled with another page of notes. "A-are you sure? I mean, there's this whole issue of the negative readings…" She scratched her arm awkwardly. "I mean, it could be faulty wiring or something; I _did_ put it together pretty fast…"

"I do not think…well, I can show you. I think you both will find this as intriguing as I do." Gaster's hands were moving so fast he threatened to lob the apple through one of the windows, though he suddenly stopped. "Sans, are you able to walk? I do not want to risk you teleporting into a room outside of time."

"I'm fine.," Sans assured, then shrugged. "I've gone to the kitchen and back a couple times; I'm ready for a marathon at this point, honestly."

"Sans, please be serious."

"I'm always serious." He winked as he got to his feet, lifting his arms and arching his back, getting a few pops from his spine. "Well, that might be a _stretch_." He waited for a moment, making sure he was balanced, then stuck his hands in his pockets. "Ready whenever you guys are."

Gaster watched him anxiously for a moment, tossing the apple between his hands, then nodded. Alphys got up as well, and the three of them made their way down to the grey room. Sans wasn't doing too bad until the stairs…those weren't fun. As he slowly made his way down, Alphys hovering behind him just in case, Gaster—already at the machine—called, "Alphys, leave the door open!"

" _What_?" Sans' head shot up to look at the scientist, then back at Alphys as she did just that. "What if someone sees?"

"I would rather have that than risk smoke inhalation if the experiment does not work," Gaster said, tapping at a few of the buttons.

"But we don't have lungs."

"I have lungs!" Alphys interjected. Gaster smiled.

"And a good scientist will _always_ look after a good assistant's health when possible," he said. "Now, both of you, come here."

Alphys waited for Sans to take one last breath, then they both made their way to the machine. Gaster pointed at the screen. As usual, several lines were bouncing at once, but one remained at the bottom of the screen, with no apparent sign of fluctuation.

"You see?" Gaster tapped on the static line. "Over the past few days, it has fallen—gotten 'darker,' so to speak, and it has not risen at all since yesterday."

Sans' browbone furrowed as he leaned in. "But that's impossible."

"It absolutely is," Alphys agreed. "If these readings are negative, then we shouldn't be here. The machine must be broken." She frowned at the screen for a long moment. "Unless…"

Sans looked up at her; Gaster grinned.

"Please, finish your thought."

Alphys puffed out her cheeks. "Unless this is a different timeline?" Her eyes widened. "But that would mean all these lines aren't EM readings for the Underground, but…no…"

Sans' sockets widened as it clicked. "Are all of these _different timelines_?"

"Yes!" Gaster was practically bouncing. "Well, at least, that is how it would appear. We should have realized ages ago!" He tapped on the screen again. "As we surmised with the study group, a 'reset' moves you along timelines—every decision ever made splinters off into separate timelines, there is an infinite amount of them. For instance, Sans, let us say you started here…" He tapped on one of the lines. "…then you moved here…" He moved his finger down to the next one. "…and then ended up here." He tapped on a third line. "So naturally, when we programmed the machine, we would need to be able to see several timelines." His sockets were bright as he looked at them. "We cannot waste this opportunity any longer! If we can test the machine, we can see _where_ the apple travels to!"

Sans looked at the screen with concern. "What if it ends up in the, uh, dark timeline?"

"Then we can see if that brings any life to that line."

Alphys shifted back and forth. "But…we haven't tested this…I mean, I'm pretty sure it's solid and won't, y'know, _blow up_ , but it's still pretty dangerous."

Gaster laughed giddily, tossing the apple up in the air before catching it. "Then we shall prepare a speech for this brave apple if it does not make it. Sans, check the main controls, make sure the math is correct; Alphys, one last look at the blueprints—if I recall, they are on the workbench, along the wall."

They both nodded, and Sans glanced at Alphys as he headed to the controls. "I've never seen him like this," he whispered. Alphys shook her head.

"Honestly? This is nothing compared to how excited he was when we finally extracted DT." She shrugged. "But I guess that's how he got to be Royal Scientist."

Sans chuckled. "So you freaking out over Mew Mew is practice for when you take over?"

Alphys went bright red, and she gave him a little whack with the blueprint. "Shut up!"

Sans laughed as he turned to the screen, checking the coding. All the equations seemed to be right; still, couldn't be too careful.

He looked up with a small laugh as Gaster, tossing the apple from hand to hand, finally dropped it. "Aw, Gaster, you hurt its _peelings_."

Gaster shook his head at the awful joke. "One moment, I will get our subject."

Sans returned his focus to the equations, cheekbones lifted; Gaster's enthusiasm was contagious. Just a few more lines to—He jumped as he heard a door slam, then again as there was the clang of bones against metal, and the apple rolled away from the machine.

"Gaster?" he and Alphys called at the same time. The scientist, now blinking from the impact, had stumbled into the main pod of machine. Sans recognized the quick, angry signs his hands made; obviously the fall must have hurt. Gaster took a breath and rubbed his head.

"I am fine, just…er, clumsy; it would appear the apple found me rather than the other way around. Give me a moment to get up."

Both Sans and Alphys gave a sigh of relief.

But then…

…something slithered around Sans' ankle.

It all happened in the span of one second, though it seemed much longer: first was the feeling of his heart dropping to his feet; next was the realization he had felt this somewhere before; finally, his brain worked and he pulled his foot up. But the _thing_ tugged, and suddenly he was falling, and just as suddenly he wasn't, now grimacing as his skull slammed against the console.

"Sans, oh my god! Are you all right?" Alphys quickly pulled him back up.

"Ow…yeah, I do—" Sans was cut-off as the whir of machinery filled the room, followed by a piercing, soul-tearing scream.

He had accidentally turned on the machine.

" _GASTER!"_

Alphys looked up and let out a scream, while Sans did everything he could to shut off the machine. Nothing worked… _why was nothing working?_ His eye blazed blue as he slammed his fist down onto the console, but it did nothing.

" _GASTER!"_ He gave up on the buttons, and pushed himself away from the console to charge toward the machine. Two claws quickly grabbed him and pulled him back.

"Sans, you can't!" Alphys was just barely able to hold him back, despite the way he struggled against her. Gaster had stopped screaming, but Sans couldn't get the sound of it out of his skull. He kept crying out for the other skeleton, unable to turn away. Gaster's face was caught in an awful grin, and the cracks above and below his eyes spread, growing larger. His hands twitched something incomprehensible as the color faded from him.

" _ **GASTER!**_ "

A massive flash blew through the grey room, and Sans was just barely able to see the scientist melt to the floor. By the time he stopped seeing spots, the machine was smoking, but there was nothing left.

He was gone.

Sans' chest was the tightest it had ever been. _No no no NO._ He gripped his skull, trying to get any kind of air into him.

He had to write this down.

Without a word, he pushed past Alphys and grabbed a pen. The blueprint was closest. He scrawled out four words, before he could forget.

 _gaster gone. melted. machine._

"Oh my god!"

Sans whirled around, legs wobbling. Alphys was staring in shock at the machine.

"What the hell happened?"

Sans looked at her in disbelief. "Are you _serious_?" he asked sharply. Alphys shrank back.

"Wh-what…?" she asked timidly.

"Gaster! He's gone! He's…"

"Erm…who?"

Sans' sockets widened. It was starting. Alphys didn't remember him. Soon he wouldn't either.

"Oh, god."

He quickly turned and looked what he had written. He couldn't forget. He _could not forget._

He waited, reading over the four words over and over, every time worried that they would lose their meaning.

But they didn't.

Sans shook, bones rattling. What did this mean? Why didn't he forget?

Was there a chance…?

He quickly ran toward the stairs, nearly stumbling as he did but not stopping. There was no time.

"Sans!" He heard Alphys chase after him. He couldn't stop. He had to get outside for this.

"Sans, stop! What's the matter wi— _oh my god!_ " she cried shrilly as a wave of bones blasted the door from its hinges.

He had to get outside.

No, he had to get to another timeline. One where Gaster _had_ to still exist.

He could survive one more reset.

"Sans, stop, you're not in any state to go out like this!"

He finally stopped for a moment as he stepped into the snow, sucking in Snowdin's icy air and letting it out in shaky breaths. He looked up at Alphys as she stepped out from the grey room.

"Sans, seriously, you're freaking me out," she said nervously, looking at him with concern. He swallowed, then lifted a hand in a small wave.

"I'm sorry. I gotta…I gotta go," he said, voice trembling.

"You aren't making any sense! Where are you—?"

"See ya, Alphys."

"What? Sans, _wai_ —"


	17. don't forget

It turned out that skeletons _could_ throw up.

Sans trembled as he wiped his mouth, looking around. How far back had he gotten? Was this his room in the Core or his room in Gaster's house? The light coming from the window was white—Gaster's, then. He'd gone back less than a week—much less than he had the last two times. But that was all he needed.

He pushed himself out of bed, barely avoiding the mess of magic and dust and…something red. What was-No. Didn't matter. Not now. He stumbled a bit as he shoved his feet into his slippers; the room was spinning, but there was no time to lose. If he was in a different timeline, that meant that there was a chance—maybe even a good chance?—that Gaster was still here. After all, he was still in the house, right? He took a breath and, with the familiar _whoosh_ of air, was in Hotland.

 _Ohh._

That had been a bad idea.

Black edged into his vision, and he leaned against the lab door, taking deep breaths as another wave of nausea hit him. God, he really was in bad shape. Was this from the experiment or resetting? Was he about to melt like the others?

He shut his eyes and set his jaw as much as he could. _Not now_.

He pushed himself up, trying to keep himself from swaying, and banged his fist on the door. Gaster had to be in here. He'd open the door. He'd freak out and tell him to get back to bed. He'd worry about the reset. He'd—

The door hissed as it opened. Sans looked up with wide sockets.

 _Please._

"Sans?"

His shoulders slumped as Alphys poked her head out. She let out a gasp.

"Oh my god, you look _awful._ What h—?"

Sans waved his hands and shook his head. "Gaster," he said hoarsely. "Is Gaster in there?" Maybe he was down in the lower lab? There was still a ch—

"Erm…who?"

He blinked several times. _No no no._ He couldn't leave it there. There _had_ to be a chance. He took a step forward.

"Gaster! W.D. Gaster! He's your boss, Alphys!" he shouted. She shrank back, eyes wide.

"S-Sans, I-I don't…"

Sans let out a frustrated grunt, and his voice was strained as he asked, "The Royal Scientist? The one who made the Core? Come on, Alphys, I know you know who I'm talking about!"

"I really do-do-don't!" Alphys looked as though she were about to cry. Sans took several breaths and rubbed his skull. Finally, he looked up at her. One last try.

"Then how do you know me, Alphys?" he asked, voice clipped but much quieter.

She had hidden her face behind her claws, and she peeked out at him, a strange, slightly blank look in her eyes.

"Erm…well…doesn't everyone?"

Somewhere deep in his center, Sans felt something crack. He took a few wheezing breaths. He'd really done it this time. He'd ruined _everything_. He shook his skull before pushing his way into the lab.

"Sans, wait! You can't—!"

"I know what's in the lower lab, Alphys! You…you and Gaster…we did an experiment down there! With Determination!" His head swam again as he walked inside. Everything was laid out differently. Where was the chalkboard? The tables? He stopped and held his head, swaying a bit. If he could just _focus_ , he could find…he could…

He shut his eyes, just for a moment.

* * *

"…a-and he just collapsed! I-I didn't have Papyrus' number, but you…erm, I mean, you talk to him a lot, right? S-so I figure you'd be able to, to let him know. But, _god_ , it was so scary!"

"Hey, hey, you're fine, Alphys. I'll take care of it from here."

"A-are you sure? I mean, I mean, god, I called you right in the middle of work and—"

" _Alphys_. It's really fine. Hell, half the time I call you at work. It's one of the perks of being the boss. And, y'know, I'm still technically this jerk's boss even if he hasn't shown up to work in weeks."

Sans half-listened to the conversation, only about 45% conscious. He sighed, trying to get back to sleep, but grunted as he felt himself hoisted up and slung onto a metal shoulder.

"I'll get him back to his place. You really can stop worrying." A pause. "Do you want me to come back after I drop him off?"

"N-no, I-I-I'm fine now! Re-really!"

"You're the _worst_ at lying. I'll come over after work. You said you found a new anime yesterday, right?"

"Um, erm…yeah."

"Is it a fighting princess one? _With swords_?"

"That's, erm, tha-that's what the cover looks like?"

Sans groaned as he was bounced by what he guessed was particularly enthusiastic fist-pump.

"Then I'll _be here!_ "

He heard the _hsst_ of the door opening and closing, and he groaned again as he stirred.

"Heya, boss," he mumbled, cracking one socket open. A yellow eye narrowed at him, and Undyne huffed irritably.

"Awake, huh, punk?" she snapped. "What the hell is your problem?"

"I'm sick." Getting sicker the more Undyne's shoulder bounced.

"So sick you got all the way from Snowdin to Hotland?"

Sans shut his socket again with a sigh. "It's a long story."

"Yeah, well, the ending sucks. You _do know_ that you just about set Alphys into a nervous breakdown, right? And Papyrus is gonna flip if he finds out what happened."

Sans opened his socket curiously. " _If?_ You're not gonna tell him?"

"I don't _want_ to, but I will if I have to." She huffed as she adjusted her hold on Sans' ribs. "Look, the only reason I put up with your crap is because I like Papyrus. I would have fired you before you even _started!_ "

"Undyne, I'm…"

"So it really _pisses me off_ that you did something like this when you've got someone worried sick about you!"

Sans sighed and let his head fall forward again. He _really_ didn't need this right now. Undyne huffed again.

"I better not catch you harassing anyone after this, especially Alphys," she said in a low voice. "Because I _won't hesitate_ to kick your bony ass."

"I know, boss."

"And you _better_ make it up to Papyrus. He's sacrificed some of his turf so he could check up on you, and you _know_ how much he likes patrolling."

Sans grimaced; not only was this _really not helping_ , but she gestured way too much when she talked. "Undyne, seriously, stop."

She frowned at him. "Or what?"

"Or I will literally throw up all over you."

Undyne stopped. "Can skeletons do that?"

Sans nodded.

She was silent for a few moments, then quietly replied, "That's…cool, _I guess,_ " before continuing the trek back to Snowdin. He could still feel irritation radiating from her, but at least she was quiet now. His head bobbed as they exited Hotland; he must have dozed off in Waterfall, because all at once he was roughly plunked down in front of Gaster's house.

"There. My work's done," Undyne said gruffly. "If I don't see you at your post in a week, I'm coming to your door, and you're getting a _spear_ in your _face_. No more of this lazy 'I'm sick' crap."

Sans gave her a weary salute, then leaned against the door as she stomped away. He shut his eyes and took a long breath. He wanted to sleep. Really, he wanted to sleep _forever._ But despite the way his bones ached and his brain was fizzling out, that knot of anxiety from when he'd woken up hadn't eased one bit. He had to go look at the machine. He had to make sure the Gray Room really was intact. Maybe…there was still a chance…Gaster…

"Sans?!"

Sans jumped, sockets flying open to see his brother gaping at him.

"What are you doing out here?" Papyrus asked, alternately waving at Sans and a pile of snow outside the door. "You're supposed to be in bed!"

Sans leaned against the door again. "I, uh, went for a walk."

Papyrus frowned, brushing some snow from his brother's skull. "I appreciate your attempts at fitness, but even I, the Great Papyrus, think that should wait until you're better!"

Sans' cheekbones lifted a touch. "Yeah. Guess that was kinda dumb." He moved back a bit as Papyrus unlocked the door. "Hey, Pap, humor me real quick: how'd we get this house?"

Papyrus looked at Sans curiously for a moment, then, as he bustled Sans into the house, said, "You said you got it from your other job. The not-sentry one." He nudged Sans toward the sofa. "I'll make dinner! The last time I trained with Undyne, she taught me how to cook noodles! Next week we'll be making sauce!"

"Sounds great." Hopefully that didn't sound too strained. So Gaster hadn't existed in this timeline. Or…any timelines. He had to get to the Gray Room, but…definitely not with Papyrus keeping watch on him. He let out a short, soft sigh, then flopped onto the sofa. If he couldn't work, he could at least rest.

"Hey, Pap?"

"Yes, brother?" Papyrus poked his head out from the kitchen. Sans looked up at him for a moment, then lifted his hands.

"Does this mean anything to you?" he signed, keeping his movements slow. Hopefully his sockets didn't look too desperate. Papyrus' browbone furrowed.

"Is that some kind of hand dance?" He gave Sans a bright grin. "I like it!"

Another crack from his middle. He kept his voice in check. "I, uh…I thought you might."

* * *

Gaster had been right.

When he'd reached the Gray Room, it was left exactly the way it had been before his reset. The blueprints were right where they had been left, "gaster gone. melted. machine _."_ still scrawled over the diagrams. The timeline reader was still beeping along; in one line there was a massive dip, in the one below it, a massive spike. So. That's what a reset looked like.

The machine had been the hardest to look at. Obviously, of course, it was the thing that had…done whatever to Gaster. But there was also _so much_ that needed to be done.

So it was time to get to work.

He tried. He tried very hard, considering he had no experience with machines outside of watching Alphys. But he couldn't get a fallen panel of metal to flatten. He burned himself with the soldering iron when he tried to re-attach the panel to the side of the machine. The panel, _naturally,_ fell off. The _screws_ wouldn't _fit_ in their _designated holes._ When he opened the console and saw the mass of frayed wires in a tangled heap, he almost started to cry.

He had the blueprints! Why weren't they _making sense_? Why was _nothing working_?

Frustrated and once _again_ exhausted from the effort and strain from the past few hours, he hit his skull with his fists to try and get his brain moving. "Come _on,_ Sans," he growled to himself. "You can do this. Just _think like a scientist!_ "

Instructions. There had to be instructions in here for…any of these tools. At least for the console. He tore the room apart, looking in toolboxes and throwing open the drawers, hoping for _something._ He stopped as he reached the drawer closest to the door. Inside was a laminated badge—it must have been Gaster's, though he'd never seen him wear it—and a book. Not a guide for building time machines, unfortunately. Rather it looked like some sort of album.

Huh.

He picked it up and looked at it for a moment. He should get back to work, but curiosity pulled at him. Probably a side-effect of thinking like a scientist. He opened the book and flipped through.

The start had quite a few pictures that looked very old. Gaster—head and hands intact—solemnly shaking Asgore's hand in what looked like some sort of very formal occasion; another, much more candid one of him and another monster—she looked like Asgore, was that the queen?—chatting. In this one, Gaster's hands were blurred. Huh. It was weird to see him so young.

Sans' brow furrowed as he flipped ahead. Abruptly, there was a shift from very old pictures to very recent ones. The group photo…god, Sans couldn't even name any of these monsters now…and more candid ones. A rabbit and lava monster in intense discussion; a fish-monster throwing up a peace sign; the same fish-monster and himself pulling a face at the camera; one of him and Gaster in deep discussion. Once again, Gaster's hands were blurred in the shot. He turned the page and blinked in surprise as a notecard fluttered to the ground. His head tilted as he leaned down to pick it up.

 _Oh._

It was a doodle he'd done while he was recuperating. Just a little one, and even worse than the ones he did while thinking. He'd probably done it after a dose of meds; after all, why else would he have drawn three skeletons smiling?

It looked like those family portraits kids in striped shirts would make.

Sans swallowed hard as the picture blurred. He shook his head to get a hold of himself, but two big tears still escaped when he shut his sockets. Then two more, rolling off his cheekbones and down his stuck smile. Then two more, four more…then more than he could count. He covered his face with his free hand, trying to get a hold of himself and hating the whimpers bouncing off the walls as the tears just _wouldn't stop_.

God.

He was just _so tired._

He didn't know how long it took, but finally the tears just ran out. He gulped a few breaths as he wiped his face with his sleeve. He had to get himself together; it was one thing to cry like a dumb kid in a room outside of time, but upstairs? What was the point of being upset over someone who never existed here?

He took a long, shuddering breath as he finally calmed down. He could almost, _almost_ feel a fluttering hand rest on his shoulder as he looked back down at the card. He swallowed hard once more, then grabbed the pen from the blueprints, scribbling two short words above the drawing. He probably wouldn't need them, all things considered, but…still.

Just a reminder of what he'd almost had.

He took another breath as he tucked the notecard back into the album. He couldn't work anymore today. He needed to just _sleep_. He looked at the album for a moment longer, then left it out on the table. He'd put it back later. Slowly, he pulled himself away and headed up the stairs to go straight to bed.

A bit of the card stuck out over the edge of the album, with the two words just barely peeking out over the corner.

 _don't forget._

* * *

Something was off today.

Sans laid in his bed for a few moments, trying to figure out what it was that felt so… _wrong._ His room looked the same as it always did, even in the dark. He was still a skeleton. They were underground. He got up, switching the off button on his alarm as he did so—he didn't know why he kept setting it, he'd sleep through it anyway—and heading over to the room next door. Ever so carefully, he opened the door and peeked in. He was greeted by light snores accentuated by the occasional "Nyeh-heh-heh," and the light from the hall showed a pair of bony feet sticking out over the edge of the mattress. Aside from needing a bigger bed, everything seemed fine in Papyrus' room. He shut the door to let his little brother sleep, then headed back to his room.

Once he shut the door, he stopped.

He had done this before.

This was the day he went and met Gaster.

He was _right back where he started._

Static filled Sans' head, and he abruptly dropped to the floor. He gripped his skull as it pounded. _No, no, no._ This couldn't be happening. He couldn't be this far back.

That meant everything he had done had been for _nothing._

He felt a strange bubble in his chest, and a strangled noise escaped through his teeth. Another one followed, more fully formed. Then a giggle. Soon enough, he was laughing uncontrollably, unable to stop even as he felt the bottom of his sockets grow wet.

What was the point? Of _any_ of this?

 _Nothing mattered with resets._


	18. Judgement

The hysteria ebbed after a few minutes, and he was left with… _nothing._ He laid back on the floor limply, staring dully at his ceiling. He felt…empty. No drive, no anxiety…the static in his head had subsided, but he couldn't even begin to think of a way he could fix this.

Because there wasn't any. Whatever he did would just be undone.

 _It. Didn't. Matter._

This time he didn't laugh. He merely sighed and shut his eyes, only to grimace as he heard the door open.

"Sans? Are you in here? You weren't— _oh my god!_ Are you all right?"

Sans covered his face. God, he didn't need this. "Papyrus, not now," he said dully. "Just…leave me alone."

The door creaked open more. "Are you hurt? Did something happen?"

"Pap, seriously, _not now._ " An edge crept into Sans' voice. Papyrus didn't know about the resets. He didn't know how much time they had lost. He didn't know _anything_ about this. It must be _nice_.

Papyrus hesitated, and Sans tensed as he heard a tentative step forward.

"Sans, really, if…if there's something wro—"

"Papyrus, _GET OUT!_ " Sans snarled the words out as he finally sat up. Papyrus immediately shrank back against the door, sockets the widest he'd ever seen them.

For the first time in his life, it looked like his brother was speechless.

Sans blinked a few times, his breathing coming in quick pants as horror washed over him. He'd never yelled at Papyrus before. _Ever._ He swallowed and shook his head.

"P-Pap, I-I…"

"It's okay, brother." The reply was instant and genuine. Of course it was; this was still Papyrus.

A wave of guilt crashed over Sans. He hunched forward, holding his skull again as he shut his eyes tightly. He heard a small creak of bones as Papyrus shifted his weight.

"Do you…do you still want me to leave? Would that help?"

Sans nodded mutely, not daring to look up. He heard the shuffle of Papyrus' feet, then let out a shaky breath as the door shut.

Now would have been a good time for a reset.

* * *

He let out a gasp as he was enveloped by coldness. He sat up quickly, only to sag as he realized he had just fallen in the snow. He must have dozed off and fallen off his stool. Silly him for thinking that something _interesting_ had happened.

Sans slowly picked himself up and got back to his position at his post, cheekbone firmly planted on his fist as he stared ahead dully. What a waste of time. _All_ of this was a waste of time. The days dragged on—there was no research now, of course, and he couldn't bring himself to do anything remotely close to science after…everything that had happened. Really, if it weren't for Papyrus…

He stretched. No. That was a _baaad_ train of thought.

He wished he could just settle into numbness—after all, it wasn't like there was anything he could do—but the sheer _bitterness_ consuminghim kept him from that marginal comfort. He was sure it would have been obvious to everyone if it weren't for his damned grin—he could barely look into mirrors these days; it just reminded him of the hell he had gotten himself into.

If the waiting had been irritating before, now it was _torture._ And there was still, what, six months until he got to the day Gaster vanished. For now, all he had was a cycle: go to work, doze at work because _nothing would happen_ , go home. Things had been a little shaken up when Papyrus got them their sentry jobs two weeks ahead of schedule, but then it was back into the same routine, just in a new, much colder location and with the occasional chewing out by Undyne for slacking off. But really, what was the point in trying? Another reset could come at any time, and then they'd be right back to where they were. The same six months, _over and over and over and_ …

He cracked his neck. Yep. Tonight was a Grillby's night.

He didn't go to Grillby's all too often; most of the time, it only seemed to make things worse. Half-memories of the fun times with long-gone researchers would bounce around his skull, and he would just get _so infuriated_ by everyone there. They didn't know about resets! They didn't know that they were _living the same loop!_

Why couldn't _he_ still have that ignorance?

Half the time he had to leave before he could even order, lest he crack and tell the whole bar about timelines and resets and how their whole existence was a _joke_ due to the whims of some _freak_ who kept jumping backwards.

Tonight, though, wasn't one of those nights. He stayed for a drink. Then several more. After several crackling whispers from Grillby of "I'm not serving you any more…do I need to call your brother?...I'm about to close up…" Sans finally pushed himself away from the bar. Home, he needed to get home.

Where was that again?

He stumbled out of Grillby's, looking for the big house at the edge of Snowdin. That was home. That was where he'd felt safe last…like a reset couldn't touch him. So that probably wasn't right in this timeline, but…

He tripped over a snow pouf, landing in Gaster's front yard. He giggled to himself. Gaster would freak if he saw him out here after the experiment…

"Sans?"

Sans pulled his head up with some effort and squinted at the skeleton looming over him. _Was_ that Gaster? Maybe…

"Brother, are you all right? Grillby called and he said—"

Sans let his head fall back with another giggle. It was just Papyrus. Of course. He was a good brother, that was a constant. He lifted his arms and waved his hands.

" _Heyy_ , Pap, look! I'm making a _boneyard!_ " He let his arms drop with another giggle. "Geddit? Because I'm a _skeleton_." He lifted his head again to look at Papyrus, who merely returned the look with something that looked kind of like worry. He leaned down and pulled Sans to his feet, hands out to keep him steady as he swayed.

"We should get home; it's no fun coming to work if you're already there!" Papyrus' cheeriness seemed a bit strained, but Sans pushed that worry away as he shook his head.

"No…no, 'sfine." He waved at the house. "This…this is…we live here! With…wait…uh, no, wait…" He held his head. "Which timeline…oh, _god,_ it doesn't even matter!" He shook his head and swayed so much Papyrus had to grab his shoulders to keep him upright.

"We live in the Core, Sans," he said patiently. "We'll walk back together!"

Sans shook his head again before letting it fall against Papyrus' sternum with a clatter. "No…no, no, it doesn't _matter_ , Pap! _Nothing matters!_ We'll jus'…everything's jus' gonna be reset again and again and-and there's _nothing_ I can….I mean…" He shut his eyes and sighed. "Forget it. You won't remember. Just me."

Papyrus was silent, and Sans kept his head down. After a moment, Papyrus drew away. He probably thought Sans was crazy after that. Maybe he was by now. Maybe he—

He let out a little grunt of surprise as he was very, very carefully slung on Papyrus' back. He slumped forward with an airy little laugh.

"Remember when I did this t'you? When you…when you were just a baby bones?"

"Yeah."

Sans let his head fall forward. "When Mom'n Dad were still around. Ya don't remember them, do you?"

"Not much."

"An' you…you don't remember Gaster; no one remembers Gaster."

Papyrus was silent. Sans shook his head against his brother's shoulder, shutting his eyes as Papyrus walked.

"I know why you're like this," Papyrus said quietly. Sans' eyes opened, and his head shot up.

"Y'do?" How would Papyrus know about the resets? Especially in this timeline? His sockets widened as Papyrus nodded.

"You're overworked!"

Sans blinked, and he couldn't help his giggle. Of course. Good ol' Pap, always worried about the work. Papyrus glanced back at him.

"You don't talk about it much, but…but I know you work a lot and—"

"Nah, not so much. Lost one of my jobs." Sans' head sank back down against Papyrus' bony shoulder. "Ev'ryone's gone. Can't fix the machine."

Papyrus gave a little huff as he adjusted Sans. "That's it, though! You shouldn't have to worry about that!" He was silent for a long moment. "Tomorrow I'll go and get a job in the Core!"

Sans' head abruptly turned to stare at Papyrus in shock. "No! No, no, Pap, y'don't…ya really don't need to do that! Y…you'll have to drop outta patrolling if y'do that!"

"I know."

"But…but the Great Papyrus…"

"The Great Papyrus wouldn't be very great if he didn't help his brother." Papyrus turned his head to give Sans a bright smile. "And I already know I am very great at puzzles! And…and maybe it'll be easier to make friends that way!"

Sans felt sick. God, he was _completely_ fucking up this timeline. He shook his head again, awkwardly squeezing his arms around Papyrus' neck to hug him. "No…no, no, buddo, you don't…don't _do_ this! Okay? I know…I know what's gonna, gonna happen and—"

His head began to bob… _no_ , he couldn't fall asleep, not now. He had to tell Papyrus what a bad idea this was! He tried to speak again, but his sockets were shutting and he couldn't get his brain to process what words to say. He had to…he had…

His head nestled down against Papyrus' shoulder, and he sank into a troubled sleep.

* * *

It was still night when he woke up; something about the stillness told him the Underground was still asleep. He didn't open his sockets, instead burying down into the blankets. Blankets? When had he ever put blankets on his bed?

Oh. Right. Papyrus had taken him home. He must have made the bed, too. Something twisted in his chest as he remembered the state he'd been in, only to twist harder as he remembered something much more awful.

Papyrus was about to give up. All because Sans was a wreck.

He sat up quickly; his head still swam a bit, but that wasn't important. He had to fix this. He _had_ to. Maybe one more reset…

No.

He needed to get to the rootof this problem. It was time to stop trying to go back to fix things, to stop going about this the clever way. Really, he needed to _stop_ thinking like a scientist.

After all, he really was more of a brute-force guy.

He threw himself out of bed, shoving his feet in his slippers and grabbing his jacket before he teleported out.

The Wishing Room was quiet, as it always was. Sans didn't have a literalheart, no, but _something_ was thrumming in his middle as he made his way to the center of the room. He took a few deep breaths before looking around the room.

"So you gonna show up or not?" he shouted to the empty room, the echo flowers erupting in repetition. "Come on, don't be shy, I know you're causing the resets! I know you _killed my brother!_ So why don't you come out here and fight _me?"_

"Again."

Sans whirled around as he heard a small voice. Amongst the echo flowers, all chanting "again again again," a small yellow flower lifted its petals to reveal a friendly smile.

"Howdy! I'm Flowey! You must have forgotten!" His bright smile shifted into a smirk. "But we both know what's going on here."

A ring of bullets appeared over Flowey's head, and he let out a horrific laugh.

" _So let's just get this over with._ "

The bullets shot straight at Sans, but he dodged far faster than he thought he could. Must be from the experiment. He wasted no time in summoning a wave of bones, aiming them low to try and cut Flowey down, but the flower merely popped underground with another laugh. Sans scanned the area for him, fingers twitching and ready to summon more bones. He froze, chest tightening, as he felt something slither around his leg.

"Remember this? This is how _we_ got rid of that old man."

Sans sucked in a gasp, and he teleported away before the vine could tug him down. He whirled around to glare at Flowey, eye blazing blue.

" _You!_ "

Flowey rolled his eyes. "It wasn't like he was any fun." If Sans didn't know any better, he'd say there was a pout on the flower's face. "He only cared about _science_ and _morals._ He didn't even help…" He stopped, then gave a little laugh as an awful grin spread on his face. "Well, it's not that big a loss. No one remembers ol' _What's-his-name_. Soon, I bet _you_ won't ev—" Flowey was cut off as a bone struck him across the face.

 _"Shut up!_ " Sans launched another few bones at the flower, breathing hard. "I've had it with you, you little _weed._ For once I'm gonna do my job, and make sure you _never_ ruin _anything else_ , in this timeline or any other!" He teleported to Flowey's other side, wasting no time in attacking again. Much to his surprise, the bones came flying back from a vine's hard whip.

"This is SO BORING!" Flowey yelled. " _YOU'RE_ BORING! _"_

Another vine whipped out, knocking Sans back into the water. As he struggled up to his feet, a bullet grazed his arm; he staggered back in surprise. That…hurt a lot more than he anticipated. He looked up as he heard Flowey laugh.

"You're such an _idiot_. It's the same fight every time, only you've gotten _worse_." He popped back into the ground, then up to the edge of the water, face smug. "You wanna know _why_ you're in such bad shape? You wanna know _why_ all your friends are gone? It's because you don't know how to _save._ "

Sans gripped his arm hard, head spinning too much from the pain to speak. Flowey laughed.

"See? I bet you're gonna dissolve from that teeny hit!" Flowey's smile died. "And it'd serve you right. _I_ did my resets the right way. _I_ had a save point; I could keep going back without hurting anyone permanently. But then _you_ and your _friends_ kept resetting and throwing everything off. I haven't been able to do _anything_ until I took care of that scientist." He laughed again, though this one was bitter. "That was the first exciting thing to happen. I actually felt like I _did_ something." A vine wrapped around Sans' ribs, and he was in the air for a brief moment before crashing into the wall. He grimaced, staying down for a moment as he tried to get his bearings. Flowey laughed again, this one manic, and the echo flowers repeated it over and over.

"It doesn't matter what I do! I'll reset and maybe I'll help everyone, or maybe I'll kill everyone! I don't have a limit like you because I'm not an idiot!" He made his way over to Sans as the skeleton got to his feet. "Maybe I'll kill your stupid brother in front of you a couple times—or I'll get him into the Royal Guard and he'll get killed by a 'human'. Or maybe I'll just kill YOU again and again and AGAIN!"

A slew of bullets came at Sans, and he stumbled back as he was hit. Something red spurted between his teeth. He lifted his hand to his mouth, looking at the red stains in horror. What even _was_ this? Was this…was he about to die?

He gripped his hand in a fist.

No.

He wasn't done here. He wasn't about to let this _flower_ keep playing with the timelines. This ended _here._

That thought alone filled him with…well, _something._

He wiped his mouth and forced out a little chuckle. "Y'know, I get it. It _sucks_ knowing about resets." He lifted his head to look at Flowey, who watched him with narrowed eyes. "I mean, you said it yourself. We've done this song and dance before; hell, I must have repeated the same six months at least three times because of my own resets, and nothing changes. You start feeling like nothing matters."

He took a step forward as the thrumming returned, stronger this time. "But things are different this time around. This fight is only gonna happen _once_." Another step. Whatever was stirring in him was getting stronger, and he took a few more sturdier steps toward Flowey. " _This_ matters. Because after this, _no one_ is gonna interfere with the timelines. So I'll be frank…" He met Flowey's gaze, eye burning a bright blue as he held up a glowing hand. "…you can call it quits here, or, uh, I'm getting the feeling you've got something _really bad_ coming your way."

Flowey stared at him for a moment, then let out a giggle. "Wow. You really _are_ dumb. You must be down to one HP! What could you eve—"

The hand came down.

Immediately, _something_ formed in front of Sans. It was…big. _Really big._ Both he and Flowey watched in silence as its jaw split, and a beam of white light shot directly at the flower. Sans jumped back, and a laugh snuck out from his teeth as the light died.

"Not bad for being untested, huh?" he called giddily, summoning another two before Flowey could reply. "You can thank Gaster for this, you weed!"

As the lights hit Flowey, he threw out a few more bones, each catching the now-disoriented plant before he summoned a whole row of blasters. He felt…amazing, the best he had in a long time; there was the hint of fatigue that came from a good fight, but he could go on for _hours_ if he needed to. So maybe there was something to this Determination thing.

His thoughts snapped back to the present as Flowey, drooped over and missing a few petals, laughed breathlessly as the last ray died down.

"I guess that was kind of exciting," he said hoarsely. "But I'm bored now, so bye."

Sans froze, and he threw his hand to the side to dismiss the blasters. "Don't you even dare," he said in a low voice.

Flowey let out a weak scoff as he glanced up. "Like you could stop me?"

Well. There really was just one option here. Sans let out a sharp breath. "I'll beat you to it."

With a grimace, Flowey pulled himself up to sneer at the skeleton. "Please. You'll _die_ if you reset. I've been following you around long enough to know that. You must _really_ be an idiot."

A laugh bubbled out of him at that, slightly too-long and not all that different from the one he'd laughed at the last reset. The echo flowers repeated it back to them, sounding more manic with each repeat.

"Idiot? Oh, no…no, friend, that's where you're dead wrong." He teleported to Flowey's side, forcing the flower to turn. "See, I'm the _leading scientist_ when it comes to resets." He teleported again, making Flowey's head swivel. "I've researched this. I've _experimented._ I've _. Lived._ This _._ So, you little weed, believe me when I say that I am _fully qualified_ to tell you this."

He teleported straight in front of Flowey, sockets dark as he met the flower's gaze. "I have _nothing_ to lose. If you reset, I live, and I'll find you. If I reset, I'll die. But chances are pretty high that you won't remember me." One more teleport, right behind the flower; he leaned down whisper, "But you'll _always_ have this feeling that someone's after you. You'll spend the rest of your miserable life looking over your shoulder. Sure, it might just be paranoia. _But it might not be._ " He laughed again as Flowey's head whirled around. "That seems a pretty fitting punishment for all of this. Maybe I _am_ a good Judge."

Flowey stared at him, mouth open but silent, and Sans lifted his cheekbones and gave the widest smile he could. "Welp. Seems like that's all that needs to be said, so whaddaya say we just get to it? Three..."

He relaxed his shoulders.

"Two…"

He let out a breath, then gave one last little chuckle. What a ride this had been.

"One."

He let go, and everything faded to black.


	19. Closing Up

He let out a gasp as he was enveloped by coldness. He sat up quickly, only to sag as he realized he had just fallen in the snow. He must have dozed off and fallen off his stool. He groaned as he fell back in the snow; god, he felt awful. What had he…

Sans' sockets flew open.

 _Wait._

He'd done this before, just a few hours ago. That meant he'd reset.

 _And he survived!_

He laid there in the snow for a moment, staring straight up as his brain caught up with the facts. He really did make it. He hadn't melted. He was still solid, still here, and it was _amazing!_

A laugh bubbled out of him: not the sharp, strained ones he'd been prone to lately, but a _real_ one, one that came straight from his middle and felt _wonderful._

He laughed as long as he could; his bones ached and he was sick, but by god, he was alive.

The laughs faded, and he merely laid in the snow with a sigh.

There was no way to know if the resets would stop. And it wasn't like he could stop them. Nothing mattered, still. Another laugh bubbled up at that thought. If nothing mattered, then why had he been so stressed? That wouldn't help. If he had this much time on his hands, he might as well make the most of it. He could do whatever he wanted. Like, say, be a comedian.

He chuckled once more as he got up and brushed off the snow. Screw work, he was gonna head home and tell Papyrus—the _Great_ Papyrus—how he _absolutely_ should keep working to join the Royal Guard. He walked through the town, taking it in. God, he never thought he'd be grateful for _Snowdin_ of all places. But he supposed everything looked great when you thought you'd be disappearing into the void. He was going to do so much now. He'd help Papyrus as much as he could with his fighting when he wasn't pranking the hell out of him—he could _teleport_ , how had the possibility of pranks never occurred to him before now?—he'd tell tons of jokes and talk to people and…

He paused as he reached Snowdin's edge, looking up at the large house he still passed everyday. The windows were dark, and there was no sign of life anywhere near it.

Still…it looked like _home_.

He stood quietly for a moment, then turned and headed back into Snowdin. Looking into a bit of real estate was definitely the first thing he should do with this new _lease_ on life.

* * *

"Sans, I've nearly tripped twice now! Can I _please_ look?"

"Not yet, bro. Just another minute."

Sans guided Papyrus, hands obediently held over his sockets, to the front porch, instructing him to stay put as he pulled out the key to Ga— _their_ house. He unlocked the door, then pulled Papyrus inside. "All right, Pap, you're good. Take a look."

Papyrus pulled his hands away, and he let out a gasp. "Wowie! A house!"

" _Our_ house," Sans corrected, sticking his hands in his pockets. Papyrus looked at him with wide sockets.

"Wait, _really_?"

"Yep. Signed it all off and everything."

Papyrus was practically bouncing in place. " _We_ have a _house!_ And we live _right next to work! THIS IS THE BEST DAY EVER!"_

Sans' cheekbones lifted. "Well, we'll have to move our stuff over before we can really live here, but…yeah." He looked around the living room. "This is our house." He looked up at Papyrus and winked. "And, uh…I do have _one_ more surprise."

" _Another_ surprise?" Papyrus had gone from bouncing with excitement to _vibrating_ with excitement. Sans laughed and nodded as he headed up the stairs. He opened the door. "Here's your room."

It wasn't decorated much yet; Sans had wanted to make sure Papyrus got free reign when it came to how his room looked. But, in the corner, there _was_ one piece of furniture: a bed, finally long enough to fit Papyrus comfortably, with a red racecar bedframe.

Papyrus gasped. Sans looked up at him. "Like it?"

"It's…it's _perfect!"_ he cried. "It's always been my dream to drive on the surface!"

"Okay, I know for a fact it hasn't, Pap."

"Well, it's always been my dream since right now!" He grabbed Sans in a spine-popping hug. "Thank you, thank you, brother! I _love_ it!"

Sans' grin widened as much as it could, and he gave his brother a quick squeeze back before patting his backbone. "Hey, don't even mention it. Though we _auto_ get moving if w—"

"SANS, DON'T RUIN THIS."

Sans laughed. "All right, I'll spare you. After all, I know my jokes _tire_ you out."

"SANS, OH MY GOD."

* * *

The weeks that followed were the best he'd had since Gaster's disappearance. Sure, every now and again existential dread reared its ugly head and reminded him that this all could be reset at any moment and leave him the only one who knew about the hopeless circles they all ran in…but he mainly focused on the present. After all, there was terrible spaghetti to eat (Papyrus' newest obsession, thanks to Undyne. Sans figured she subconsciously remembered their fight a few timelines ago and was punishing him), nights to spend at Grillby's (He was always careful now; even if he hadn't drunkenly caused Papyrus to give up on his dreams in _this_ timeline, the memory was still far too fresh for him to risk another slip-up), and long patrols to spend thinking up jokes.

And, of course, there was the door.

The door was the _perfect_ place to hide out and kill a few hours of patrol-time. It was quiet, so he could nap; no one came by, so he could practice signing—despite Gaster's disappearance, he didn't want to lose the one bit of skeleton language left; and, really, you couldn't ask for a better place to practice knock-knock jokes. So for quite a few months, his routine went like this:

"Knock knock." Two knocks for emphasis. "Who's there? Scold. Scold who? ' _Scold_ out here, open up."

"Knock knock." _Knock knock._ "Who's there? Needle. Needle who? Needle little help opening the door."

"Knock knock." _Knock knock._ "Who's there? Cash. Cash who? Gesundheit."

And so on. It was fun; he made himself laugh more often than not, and that was almost as good as an audience.

Today was no different. He strode up to the door, already fighting giggles at this joke. He leaned against the door and rapped his knuckles against it twice. "Knock knock."

"Who is there?"

Sans jumped back in shock at the soft female voice that replied. Had someone been there this whole time? Oh, god, had he been assaulting someone's _house_ with knock knock jokes? He'd thought it was abandoned.

Still…the voice _did_ reply the right way. So maybe she liked his jokes? Now if only he could remember what the joke was. He swallowed.

"Uh…dishes."

"Dishes who?"

"Dishes a really bad joke."

The voice on the other end was silent, and then all of a sudden there was an eruption of loud, braying laughs.

It was _wonderful._

He quickly knocked on the door again. "Knock knock."

A snort. "Who…who is there?"

"A broken pencil."

"A…a broken pencil who?"

"Nevermind, it's _pointless_."

Another peal of laughter, along with a little pound on the door. Sans' cheekbones lifted, and he _knocked_ out a few more; the lady on the end must have been in tears from how hard she was laughing. Just as he tilted his knuckles up, two knocks came from the other side of the door.

"Knock knock!" came the lady's breathless voice.

"Who's there?"

"Old lady!"

"Old lady who?"

"Oh! I did not know you could yodel!"

Now it was Sans' turn to laugh; he wasn't quite as loud, but it was still the best laugh he'd had in a while. There was another two knocks.

"Knock knock!"

"Who's there?"

"Interrupting ghost."

"Interrupting gho—"

" _Boo!_ "

Sans blinked, completely awestruck.

Wow.

This woman was _good._

He was laughing nearly as hard as she was, and soon enough they were swapping jokes back and forth, half the time barely getting them out because they were laughing far too hard.

He was having the time of his _life._

Eventually, though, he realized how late it was. He calmed down his laughs just enough to get out a "Knock knock."

"Who is there?" Her voice was full of anticipation.

"Iota."

"Iota who?"

"Iota get going. It's just about time for my brother's bedtime story, and I don't wanna keep him waiting."

"Oh, of course." She was silent for a moment, then said, "But, if you are in the area…you are always welcome to come back."

Even though she couldn't see it, Sans winked. "Lady, you're the best audience I've had. I'd be nuts if I didn't come back."

And he did. Then he did again. And again. Eventually, it was a daily thing; Sans spent his free time coming up with new jokes, and each one brought out that wonderful braying laugh before she came back with one that was equally hilarious.

While they still told a good deal of jokes, conversations started cropping up in between as time went on. Just little things: he'd tell her about his patrol that day, she'd mention an interesting book she had read, he'd give her a great story about Papyrus, she'd tell him about how she'd gotten stuck at one of the puzzles in the ruins.

Today, she mentioned that she had wanted to be a teacher when she was younger.

"I mean, it is a silly wish, and impossible given how my life is," she said, voice somewhat embarrassed. "But…well, I have always loved learning, and I would love to share that knowledge with children."

"That's not silly," Sans assured, leaning against the door as he sank down in the snow. "I bet you'd be a great teacher. Though, uh, I hear all that attendance taking can make you _absent_ -minded."

The lady snorted, and Sans' cheekbones lifted. Once she finished laughing, she added, "And what of yourself, my friend? Surely you must have something you have dreamed of doing."

Sans shrugged. "Eh, I dunno. I, uh, well, I kinda just take things as they come right now. Less stress that way, you know?" He poked at a snow poff absently. "I, uh, I used to want to be a scientist. Even worked with the Royal Scientist for a while."

He hadn't expected to bring that up, but…well, it was hard not to feel comfortable with someone who told such hilariously awful jokes.

"That is wonderful!"

Sans shrugged again. "It was. Then…well, then it wasn't."

"Oh…I am sorry."

"Don't worry over it, lady. The appeal just kind of faded." He winced at the unintentional pun. "So I don't do much with science anymore." He grimaced. "Don't think Alphys even remembers me by now. Probably for the better."

She was silent for a few moments, then said, "I…understand. I had a…similar experience…not exactly the same, but I was disillusioned and that is why I am here." She gave a short laugh. "That is a very bad explanation."

Sans glanced back at the door. "You wanna talk about it?"

" _No._ " His browbone raised at the intensity in her voice. "But what I am trying to say is that…abandoning something is not a good idea. If I could go back…"

"You don't wanna do that."

"Well, no, it is impossible. But…my decision may not have been the best. And so long as you have the freedom to speak to the Royal Scientist again, perhaps you can mend things." She gave a soft laugh. "And then you will not become a lonely old think like myself."

Sans shook his head with a laugh too soft for her to hear. She thought he and Alphys had had a falling out.

Then again, he supposed they kind of had, even if she didn't know about it. He rubbed his patella as he thought, then gave a louder chuckle.

"Y'know, lady, I think you're right."

* * *

Sans took a deep breath as he teleported in front of the lab door, setting down the large bag of dogfood he had brought. This wasn't going to be Gaster's lab. Alphys only vaguely knew him. He'd have to act like he hadn't spent six months practically living in this lab, because in this timeline he hadn't. He took a breath, then knocked on the metal door and waited.

And waited.

And…waited.

His browbone furrowed, and he knocked again, louder. Another long silence, until he just _barely_ heard a small voice go "Pleeeeeease go away…I'm not heeeeere…"

He waited another moment, then hesitantly knocked again. "Alphys? It's Sans. I've, uh, I've brought you something." Hopefully this one had the same vague knowledge of him the one a few timelines ago did.

There was another long pause, but the metal doors opened and he was socket-to-eye with the yellow dinosaur. She frowned curiously at him. "You…brought _me_ something?"

Sans gestured to the bag of dog food. "We, uh, we have a dog problem at our place. I got this to try and get it away, but it seems to _bone-ly_ have a taste for Papyrus' attacks." He rubbed his top vertebrae. "I dunno, I just figured with all your science stuff, you might be able to use it. But, uh, if you don't, then I know some of the guards will…"

"No! No, it's, erm, i-it's a-actually perfect for a…f-for an experiment I'm kee-erm, working on." She gave him an awkward smile. "Thanks." She started to lean forward to take it, but Sans stepped in front of the bag.

"There _is_ a price, though."

Alphys shrunk back. "O-oh?"

Sans gave her a wink. "Someone told me you have the first season of Mew Mew Kissy Cutie on dvd."

Alphys' eyes widened, and she pressed her claws to her face. " _You_ like Mew Mew?" she cried. Sans shrugged.

"Hey, there's something about those technicolor cat girls that's just _meow_ gnificent."

Alphys snorted as she picked up the bag. "That's _terrible!_ " She led the way back inside, Sans following after. "Make yourself at home! Sorry I didn't look at the video screen, I, erm, I just…well, nevermind, I'll be back in a minute!" She carried the bag to the elevator.

Sans glanced up at the video screen, letting out a soft little "heh" as he saw a different anime paused on it. He looked around the lab. Like the last time he was in here, nothing looked as it did when Gaster was around. Instant noodle boxes and empty soda bottles replaced the forgotten mugs of tea, papers and figurines were everywhere, and the center of the room was more of a living space than a study area. It was like…well, no, it wasn't _like_ Gaster had never been here. He hadn't. That was that.

Sans absently picked up a page of notes and looked over it out of habit. His browbone furrowed, and he grabbed a pencil to write a couple corrections.

"Sans? What…are you doing?"

Sans looked up in surprise as Alphys was back earlier than he thought. "Oh, uh…you had a problem with one of your equations." He pointed to the one he'd been working on. "See, your equation here showed the frequency being at 6.3x 1014 Hz, but in the equation down here, you solved it with 'f' at 6.4, and it threw the equation off."

Alphys took the paper and looked at it curiously. "Oh my god, you're right." She looked up at him with wide eyes. "How did you figure that out?"

Sans winked. "It was a hobby of mine a little while ago."

" _Physics_ was a _hobby._ "

"Well, when you say it like that, it sounds like I'm _fission_ for compliments."

Alphys snorted again. "Go sit down, I'll get Mew Mew."

Sans took the chance to look around the lab once more. So it was something new. That was…okay. He wasn't as bothered as he thought he'd be. He lifted his cheekbones at Alphys as she returned, Mew Mew dvd in hand.

Things were all right in this timeline.

* * *

Actually, things were better than all right. They were _good,_ Sans realized as he got back to the house. He and Papyrus were both loving the new house, he had the lady behind the door with her great humor, and he and Alphys had tentatively planned another night to finish Mew Mew. He wasn't bitter or stressed, apart from one area. And…he needed to take care of that.

He made his way around the house to the Grey Room's door. He hadn't gone near it since he last tried to fix the machine, and was a little hesitant as he opened the door and flicked on the light. But, of course, everything was right where he left it. He'd really made a mess of the place.

He made his way down the stairs and looked up at the machine with a sigh. There it was, broken as ever. He swallowed as he walked over and set his hand on the dented metal. He'd never be able to fix this, not without Alphys, and she couldn't remember anything about it. It was just a heap of scrap now.

He stayed put for a moment, then turned and started cleaning up the room. Tools went away, blueprints were back on the tables, bits of metal were herded over to the machine. He stopped as he reached the workbench with the album still on it. Over the edge of the cover, two words still peeked out.

 _don't forget._

He was still for a moment, reading the short sentence a couple times over. This time he was…calm. Not at peace with the situation, no, but calm.

He turned and grabbed a tarp, quickly throwing it over the machine. It was over. He couldn't get Gaster back. He couldn't find him in any of the timelines. He didn't know _how_ he remembered him, because logically he shouldn't, but it was time to stop trying to go back and move _forward._

He turned back to the work bench and opened the drawer, setting the album back inside of it, beside Gaster's badge. He hesitated for a long moment, then shut the drawer with a long breath. He pushed himself away and walked up the stairs, shutting off the light as he did. He pulled the door closed once he was out, and he paused as he stuck the key in the lock.

 _don't forget._

He turned the key. The lock gave a soft click.

For the first time in a _very_ long time, he was happy. And he didn't want that happiness to be overshadowed by the past.

So maybe now it was time he let himself forget.


	20. New Pal

Time, for the first time in what had to be years, marched on. The days turned into weeks, weeks into months. Slowly, the initial thrill of being alive faded for Sans. Of course he was still grateful and focused on the present, but he wasn't Papyrus; even four resets ago, he wasn't given to being _giddy,_ and after the initial burst of joy, he'd mellowed into a slightly happier version of himself. There was, of course, always the worry that _today_ would be the day another reset happened, but for every anxious glance at the calendar, there was a wave of relief at the sight of a new day.

He still went to the door, of course. By this point, he and the lady didn't swap as many jokes, but that was only because they'd both used up their best material. So they talked, Sans sitting in the snow and leaning against the door, imagining that she did the same on her side. Truth be told, he didn't know a thing about her life, aside from her love of awful jokes, cooking, and teaching. But still, it felt like she was the closest to…being like him. Obviously without the resets, but her voice had the faintest bit of sadness in it despite her cheeriness. It was kind of terrible to admit, but…it made him feel a little better that someone else had that sadness. He didn't feel quite so alone.

And, in addition, she was probably the second-kindest monster he'd met (Papyrus, of course, was first.) After joking about living on hot dogs because of Papyrus' new love of cooking and his lack of skill, he'd come the day after to find a slice of pie, still steaming slightly, set just outside the door. He gave a little, amused laugh, then knocked on the door.

"Knock kno-."

"Who is there?" She cut in excitedly. Sans laughed.

"Noah."

"Noah who?"

"Noah-nything about this pie?"

She laughed brightly. "It is for you, my friend! As much as I admire you encouraging your brother, I know that first-time chefs do not always make good choices with their ingredients. I hope you enjoy butterscotch."

"I love the b'scotch." Sans took the plate and sat up against the door. He took a bite (and was grateful that she couldn't see; he still wasn't quite sure what it looked like when he ate, but he assumed it was pretty terrifying.) and immediately melted against the door in bliss. After weeks of spaghetti and 'dogs, this was _heaven._ He swallowed with a laugh. "So you tell the best jokes _and_ you can cook like no one else. Lady, I am _smitten._ "

He could practically hear the blush in her laugh. "Do not tease an old woman like that!"

"Listen, there are two things I never tease about: bad jokes and good food. I would marry you _right here_ if I could."

She let out another flustered laugh. "You do not even know my name!"

Sans swallowed another bite of pie before, very carefully, replying, "Well…you _could_ tell it to me."

" _No._ " Again, the sudden firmness surprised him. "It is not something that needs to be shared."

Sans swallowed. "That's fine. I get it."

An uncomfortable silence stretched between them. Sans picked at the pie, and he could hear claws tapping awkwardly on the door. She was the first to speak.

"I…am sorry, but…it really is—"

"Don't apologize. Look, I really do get it." Sans tilted his head back with a small huff. "I've got plenty of stuff I don't want to bring up either."

"I—…"

"Don't worry about it, okay?" He gave a small laugh. "Anyway, listen to this: I was wondering why this snowball kept getting bigger…and then it hit me."

She didn't laugh. Sans' browbone furrowed, and he gave a little knock.

"Lady?"

"You do that when you are uncomfortable," she said quietly. "You tell a joke."

"And you shut down. We've both got our tells." He sighed, letting his skull hit the door lightly. "Look, lady, neither of us want to go into detail about our pasts. And that's fine with me. Honestly, I'm just happy to have someone with the same amazing sense of humor I have. For all I know, you're actually a sentient door. And that's fine. I'm…" He stabbed at his pie. "Y'know, it feels like you _get it_. I mean, I don't really know what _it_ is, but…" He let out a small laugh. "I'm making this awful."

She was quiet for a long moment. "It…has been a long time since I have been able to joke at all. And I am _so_ glad you arrived. And…while I think it would be best if we kept our secrets, I do not want you to feel like you need to hide behind jokes." Another few taps of claws on wood. "I do not call you my friend for manners' sake, you know."

"I know."

"So please, do not be afraid to be honest with me."

Sans let out a long breath, shutting his sockets. Finally, very quietly, he replied with a simple, "Okay." He opened his sockets and glanced back at the door. "But, after all that, I hope you're not a bird."

"Why not?"

"They're a little _flighty_ and tend to be fair _feather_ friends."

She gave a little snort; not her usual braying laugh, but it broke the tension nonetheless. "I assure you, I would never do anything so _fowl._ " A pause. "And, if you would like, I could give you the recipe for the pie." Her voice went up slightly, the way it always did before she told a joke. "But, considering your dog problem, be sure you do not use _collie flour_."

Sans snorted, then leaned against the door, cheeks lifted. "Lady, that sounds _doggone_ perfect."

* * *

A few days later, Sans hurried up to the door, knocking eagerly. He'd had _great_ idea for a joke earlier and had teleported over as quick as he could.

"Knock knock!"

A long moment passed. Finally, he heard the soft, "Who is there?"

"Thermos."

"Thermos who?"

"Thermos be a better joke than this one."

The lady laughed, but a quiet, slightly forced one, not remotely like her normal braying one. Sans blinked, and he leaned against the door.

"What's wrong?" he automatically asked.

"It is nothing."

"Lady, that was comedy gold, and it barely got a chuckle out of you." He stuck his hands in his pockets, adding seriously, "I've heard that laugh too many times from myself. Something's up."

She was silent again, for a very long time. Sans waited patiently. However, after a few minutes, he added, as gently as he could, "If I have to be honest, then so do you. I'm ready to listen."

Another long silence, until finally, voice wavering, she said, "I…I want to ask something of you."

"Anything, lady."

She took a deep breath. "If…if a human ever comes through this door…could you please, _please_ promise something?" Before he could reply, she said, "Watch over them, and protect them, will you not?"

Sans stiffened on the other side of the door, sockets wide. A human? _Protect a human_? Was she _crazy_? _They_ had been the reason monsters were trapped down here; they'd _killed_ almost every skeleton! After a few moments of stunned silence, he shook his head.

"Lady, I…I can't…"

" _Please._ " Oh, god, her voice was so desperate. " _Please,_ my friend. I have…I have lost so many…"

Something twisted in Sans' middle as he heard one sob, muffled though it was, through the door. He rubbed his face. He was the _defense_ against humans, everything Gaster had told him, everything he'd been _trained_ for…

But…well…if he was being honest, it was hard to say no to someone who so earnestly liked bad jokes.

Another sob came from the other side of the door, and Sans lifted his hand knock on the door.

"Knock knock."

A pause and a sniffle, but eventually, "Wh-who is there?'

"Boo."

"B-boo who?"

"Please don't cry," he murmured, just loud enough to be heard through the door. He let out a sigh as he shut his sockets. "Lady…look. I _hate_ making promises. And…and with everything I've learned about humans…this isn't an easy thing to ask me to do."

"I…I understand."

He sucked in a breath. "But…for you, and just _for_ _you_ …I'll do it."

She gave a soft gasp. Sans shut his sockets tightly. If Gaster knew…

Well, he supposed that didn't matter much.

He opened his sockets as he heard a quiet knock on the door.

"Knock knock," she said.

"Who's there?"

"Tank."

"Tank who?"

"Tank _you._ " She let out a shuddering breath. "You have no idea how much this means to me."

Sans swallowed and nodded. "One condition."

"Yes, of course. Anything, my friend."

"Papyrus gets to see them." He gave a weak chuckle. "He's always wanted to catch a human."

He could practically hear her smile. "Of course, my friend. From what you have told me, I am certain he will take good care of them."

* * *

A few days passed. Their conversations got shorter, but he'd never heard her so happy in all the time they'd been talking. It must have been from his promise; he still wasn't quite on-board with it, but it wasn't like humans were usually falling into the Underground. He'd probably never need to honor it.

He came up and knocked on the door, like always, and waited. She'd been a little slow getting to him the past few days, but she was probably busy, and he was the last person to rush someone. He sat down in the snow, fiddling with a whoopee cushion he planned to use on an unsuspecting Papyrus later, and waited.

And waited.

And _waited_.

He knocked a few more times, now a little worried. "Lady?" he called, then called again.

But nobody came.

Sans let out a breath. Maybe she was sick or something. He pulled away from the door and started to walk back to town. He'd come back tomorrow; he was sure he had some good jokes for being sick, so maybe…

He froze as he heard the creaking of a door opening. Thinking fast, he teleported behind the trees. He didn't know why he was so scared; logic said that it could only be the lady. Maybe she'd changed her mind and decided to come out and meet him.

For some reason, though, a niggling little voice told him this wasn't the case.

He peeked out around a tree's trunk. Immediately, he slapped a hand over his grin to muffle his gasp.

 _A human._

This one was…small. Smaller than the one human he _had_ seen a while ago. But that didn't make them any less dangerous. He took a few quiet breaths as he planned his attack.

Just one blast, that was all he needed. The human wouldn't even see it coming; really, it was probably the merciful thing to do. And…well, when you're the Judge, you know exactly how many more souls are needed to break the barrier.

 _"Watch over them, and protect them, will you not_?"

Sans grimaced as the lady's words echoed in his skull, interrupting his planning. It wasn't like she had to know. There were tons of monsters ready to kill the thing, anyway. And he'd warned her about his hatred of promises. She'd be upset, but…but what could he _do_?

He quietly made his way out from behind the trees, though he immediately teleported back behind a tree when he stepped on a branch by mistake. The human turned and looked around.

Oh, _god._

They were just a _kid._

Sans swallowed, and he once again started following them, teleporting every time they turned to investigate. The thing was probably scared half to death.

" _You have_ no concept _of what humans are, the horrible things they do!"_

Gaster had told him what humans had done because they were scared. A scared human was a dangerous human. Monsters weren't naturally willing to fight; humans were. And he was in such bad shape that one hit, even from a kid with hardly any LV, would no doubt do him in.

But then again…what had the kid done? The flower had been a whole different story; he'd been the one responsible for Gaster's disappearance and had been resetting all over—

 _Oh._

Oh, _god._

 _This human could reset._

Whenever they wanted, without danger of hurting themself. They could put the Underground in a loop that never ended. For all he knew, they were the thing that was eating up the timelines. At the end of the day, they had all the power in the Underground—more than Asgore, more than him, even more than that flower.

Killing them now was the only way to make sure that resets _never_ happened again.

Finally, the human reached Papyrus' barrier over the bridge. They were obviously confused by it and stopped. Sans was out of trees to hide behind. It was time to make a choice.

He took a deep breath, then walked forward.

Welp. Time to be Judge.

 **"Human."**

He watched the human's back stiffen. At the end of the day, it wasn't Gaster or the lady behind the door who made this decision. It was him. He held this kid's life in his hands.

He waited a moment, giving himself the chance to change his mind. But he wouldn't. After all, he was used to making split-second decisions, and this one was the right one.

Well, he hoped so, at least. For everyone's sake.

This time, there was no going back to fix things.

He held out his hand to the human, whoopee cushion tucked inside.

 **"Don't you know how to greet a new pal?"**

* * *

A/N: Thank you all SO, SO MUCH for reading "Reset"! It's hands-down been the most ambitious fanfic (and story, really) I've ever done, and I can't thank you all enough for sticking it out even with the erratic updates and for all the follows and faves and ESPECIALLY all the lovely comments-I'm completely serious when I say that your guys' kind words helped me press forward with certain chapters that I was completely stuck on and when I debated giving it up. So THANK YOU ALL AGAIN, and hopefully I'll be seeing you all soon!

-EO 3


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